Help & Guide

Everything below covers the app in depth. For quick answers to common questions, see the Support page instead — this guide is for when you want the full picture.

Getting Started

The whole workflow starts with two steps:

Load Photos — choose a folder. Every supported image inside it (including subfolders) is added to your library.
Generate — the app automatically distributes your photos across as many pages as needed, in a randomised mosaic-style layout.

Before you press Generate

A handful of settings in the sidebar shape what Generate actually produces — worth setting these deliberately rather than leaving them at their defaults:

Number of Pages — a target rather than a hard cap. Generate uses every photo in your library, distributing them across pages while keeping each page inside your Photos per Page range. It lands on exactly the number of pages you asked for whenever the arithmetic allows — that is, when your photo count falls between pages × minimum and pages × maximum. When it can't, it flexes the page count rather than dropping photos: more pages if you have too many for the target, fewer if you have too few. Either way the app tells you plainly what it did and why, so you're never left wondering where a photo went.
Photos per Page (Min/Max) — each page gets a random number of photos within this range, which is what gives the mosaic its varied, organic feel rather than a rigid uniform grid. A tighter range (e.g. 8–10) gives more consistent-looking pages; a wider range (e.g. 4–16) gives more visual variety page to page.
Paper/Page Size — set this before generating, since it directly affects how photos get cropped to fill each frame. Changing page size after the fact still works, but frames and photos will need to be re-fitted to the new proportions. See Page Setup below for the full list of sizes, including custom presets.
Orientation and Photo Order — orientation controls whether pages are portrait, landscape, or a mix; photo order controls whether photos are placed in filename order or shuffled randomly across pages.

From there, every page is fully editable — nothing about the automatic layout is locked in. Think of Generate as a fast, high-quality starting point, not a final answer.

Tip: if you don't love a particular layout, use Reshuffle to regenerate that page with a fresh random arrangement, without touching your other pages. If there are items you want to stay put while everything else moves, see Pinning & Reshuffle.

Margins tip, especially if printing via a photobook service: many commercial photobook printers trim or fold the outer edge of each page during binding, which can quietly crop a few millimetres off — most noticeably at the binding edge. If you're printing through a service like this rather than on your own printer, it's worth setting a larger-than-default margin, particularly on the side that will sit in the binding, so nothing important (faces, text, the edge of a photo) ends up lost in the trim.

Crucially, how much gets trimmed varies from one manufacturer to the next — there's no single set of margins that's right everywhere, so treat any specific values as a starting point and run your own small test print before committing to a large order.

There are two ways to approach this, and one is considerably better than the other:

Set the page size the service actually asks for (see Photobook page sizes). Because the page then matches the book, a straightforward 20 mm all round has worked well for every service I've tested. This is the approach I'd recommend.
Use a standard size such as A3 or A4 that doesn't match the book. The service has to scale and trim your page to fit, so you need noticeably larger — and uneven — margins to absorb the difference, with the biggest allowance on the binding edge.

If you're starting a new book, go with the first approach — matching the service's own size from the outset saves a great deal of guesswork about what will survive the trim. The sizes and margins I've tested for each service are listed under Photobook page sizes.

Load vs Add, and Photos vs Files

There are four buttons for getting images into your library, and they differ along two separate lines:

Load replaces your whole library — it clears everything currently loaded and starts fresh with your new selection. Add appends to what's already there, without removing anything (duplicates, matched by filename, are skipped automatically).
The Photos buttons (📂 Load Photos… / ➕ Add Photos…) pick a whole folder — every supported image inside it, including subfolders, comes in at once. The Files buttons (🖼 Load Files… / 🖼+ Add Files…) let you pick individual image files instead, for when you only want a specific handful rather than an entire folder.

So, put simply: use Load Photos to start a project from a folder, Add Photos to fold in another folder later, and the two Files variants when you'd rather hand-pick individual images than point at a folder.

Note for Windows users: the folder picker on Windows only lets you choose folders, not individual files (and won't list the files inside a folder while you browse — that's normal, not a fault). The Load Files… and Add Files… buttons are the way to select individual photos there. On Mac either style of button can pick files or a folder, so the Files buttons are just a convenience.

Editing a Page

Click any frame to select it. A small toolbar appears above it with icons for:

📷 Pick photo — choose a specific photo for this frame from your library
🔄 Rotate — rotates the photo 90° at a time (only shown once a frame has a photo)
🔀 Swap — swap this frame's photo with another frame's
✕ Delete — removes the frame entirely

Moving and resizing frames

Resize — drag the small handle at a frame's corner
Move a frame's position — hold Alt and drag the frame
Pan/zoom the photo inside its frame — scroll to zoom, drag to reposition (without Alt)
Add a new frame — use the Add Frame button, then position and size it like any other

Tip: frames snap to nearby edges and centres as you drag, for clean alignment — the snap distance is adjustable in settings if you want it looser or tighter.

Text Boxes

Add a text box from the toolbar, then click it to edit. Each text box has two parts:

Title (optional) — sits at the top like a heading, with its own size, bold, and italic controls, independent of the body
Body — the main text underneath, which is genuinely vertically centred within whatever space is left below the title

Style controls cover font, size, colour, alignment, line height, letter spacing, background, and drop shadow — all found in the side panel once a text box is selected.

Borders

Frame Border (in settings) has two independent toggles — one for photos, one for text boxes — sharing a single thickness slider. Turn on just the one you want; they don't have to match.

Pinning & Reshuffle

Reshuffle rearranges the current page into a fresh mosaic. By default everything on the page is fair game — every frame gets a new size and position.

Pinning is how you tell it what to leave alone. Pin a frame or a text box and it keeps its exact position and size, while the mosaic re-tessellates around it instead of landing on top.

Pin a frame — select it and use the 📌 button in its toolbar
Pin a text box — select it and click the 📌 badge on its corner
Pinned items are highlighted, so you can see at a glance what's locked down

That makes it easy to anchor a fixed element — a title, a logo, a caption panel, a favourite photo — and then keep reshuffling until the rest of the page falls into place around it.

Tip: the more you pin, the less room the mosaic has left to play with. Pin enough that each remaining gap only fits a single photo and Reshuffle can still change which photo sits in each gap, but the frame sizes themselves are fixed by the space your pinned items leave behind. That's geometry rather than a fault — unpin something, or leave larger gaps, if you want more variety.

Text boxes that came from a template are pinned for you automatically, since a template's text is usually fixed branding you don't want photos landing on top of.

Page Setup

Page size options include standard sizes (A3, A4, A5, US Letter), square formats (8×8", 10×10"), and a fully custom size in millimetres. If you use a custom size often, save it as a named preset so it's available in the dropdown from then on.

Photobook page sizes

Photobook services rarely use exact ISO paper sizes. Each one specifies its own trim dimensions, so an "A3" photobook usually isn't 420×297 mm at all. What you need is the size the service asks for, entered as a custom size in millimetres at 300 DPI — and worth saving as a named preset once you've got it right, so you can reach for it again.

It's also worth establishing whether a service wants a single page or a double-page spread. A spread is two pages side by side, so it's wider. For the Photobox A3 book, for instance, a single page is 392×300 mm and the full layflat spread is 782×297 mm — and note that's not simply double, which is exactly why it pays to check the service's own figure rather than work it out yourself. Getting single-versus-spread the wrong way round is the single easiest mistake to make.

These are sizes I've tested myself:

Service	Page size	Margins
Photobox — A3, single page	392 × 300 mm	20 mm all round
Photobox — A4, single page	300 × 216 mm	20 mm all round
Photobox — A3 layflat spread	782 × 297 mm	20 mm all round
Colorland — A4	300 × 216 mm	20 mm all round
Colorland — A3	423 × 303 mm	20 mm all round
Printerpix — A3	400 × 300 mm	20 mm all round
Mixbook	US Letter and square formats	20 mm all round

Photobox and Colorland both offer A3 and A4 books; the Photobox A3 single page also scales down neatly to fit their A4, so a layout built at A3 can be reused at the smaller size. Mixbook works with the standard US Letter and square sizes already in the page-size dropdown, so there's no custom size to set up at all.

On a double-page spread, remember the binding runs down the middle rather than along an outer edge — so it's the centre of the page you want to keep faces and text clear of, not just the outside.

Verify with a test print before committing to a big project. Photobook services change their book sizes and their own layout software from time to time, so a size that worked perfectly well last year may not be right today. The figures above are a starting point from my own testing rather than a guarantee — and they're worth re-checking against whatever your service currently specifies. Ordering a single test page, or one small book, costs very little next to discovering a sizing problem after you've laid out two hundred pages.

Margins, gap between frames, and snap distance are all adjustable, and can be saved as your personal defaults (⚙ Defaults) so every new project starts exactly how you like it. If you're printing through a photobook service rather than at home, see the margin/binding tip in Getting Started before settling on your margin values.

Margins, gaps and borders are real measurements

Each margin slider shows its size in millimetres underneath it. Those are genuine physical measurements: a given slider value is the same real-world size whatever page size you're working at, whatever screen you're on, and whatever size the app window happens to be when you set it.

That matters most on a long project built over several sittings — a photobook assembled across months, perhaps on more than one computer. Every section you produce gets identical margins, gaps and border widths, so the finished book stays consistent from cover to cover rather than drifting section by section.

Page background

The page background isn't limited to black or white — choose any colour you like. Frame border contrast adjusts automatically, so borders stay visible against whatever background you pick.

You can also import your own background image. It's scaled to cover the page and sits behind the mosaic, and it's baked into the exported JPEG — so what you see on screen is what you get in the file.

Photo fit — fill the frame, or show the whole photo

Photo fit (in the Layout panel) decides how each photo sits in its frame. Fill frame — the default — crops the photo so it completely fills the frame: no gaps, but the edges may be trimmed. Fit whole photo shows the entire photo inside the frame with nothing cropped, letting the page background show around it wherever the photo's shape doesn't match the frame's. Fit is the one to reach for when the whole of every shot matters, or paired with a background colour or image for a deliberately airy look.

Coverage — let the background show

By default the mosaic fills the whole page. The Coverage slider lets you shrink it so more of the page background — a colour, or your imported image — shows through between the photos. At 100% it fills the page exactly as it always has; lower it for an airier, more spacious result. It pairs naturally with a background image or a bold background colour.

Pinned frames keep their full size (see Pinning & Reshuffle), so you can hold a title photo large while everything else breathes around it.

Coverage takes effect when you Generate or Reshuffle, and there's an ↔ Apply coverage to existing pages button to try different amounts on a layout you've already built.

Changing layout settings without regenerating

Pressing Generate rebuilds everything from scratch, which throws away the arrangement you've worked on. Five buttons let you change your mind about a setting and apply it to the pages you already have instead — your photos, their zoom, pan and rotation, and all your text stay exactly as they are:

↔ Resize pages to this size — moves your existing pages onto a different page size.
↔ Apply margins to existing pages — re-fits the frames to new margins.
↔ Apply spacing to existing pages — re-spaces the frames to a new gap. Tighten it and every frame grows into the space released; widen it and they shrink back.
↔ Apply coverage to existing pages — shrinks or grows the mosaic to reveal more or less of the page background, keeping your arrangement. Pinned frames stay full size.
↔ Tidy frame alignment — see below.

All five can be undone, so they're safe to experiment with.

Resizing to a different page shape

Where the new size has the same proportions — A4 to A3, for instance — the result is lossless: everything simply scales up or down, and it happens straight away.

Where the new size is a different shape — A4 to a square format, say — the layout can't simply scale, so the app asks how you'd like it filled:

Re-flow layout (recommended) — your photos are rearranged into a fresh mosaic designed for the new shape. This gives the best-looking result with nothing to tidy up afterwards, but any manual arrangement of unpinned frames is replaced.
Keep my arrangement — your existing layout is stretched to fit. Photos are re-cropped rather than distorted, but frames change shape, which is more noticeable the bigger the difference in proportions.

Pinned frames and text are preserved either way, so pin anything you want kept before resizing.

Tidy frame alignment

The mosaic is built by repeatedly dividing the page, and each division is made independently — so occasionally two frames end up with edges a couple of millimetres apart where the eye expects a straight line. It's too small to look deliberate and just reads as untidy.

↔ Tidy frame alignment nudges those near-miss edges into exact alignment. Nothing is rearranged and pinned frames don't move — only edges that were a hair out shift at all, and running it a second time changes nothing. It's most useful on projects built with an earlier version, since newer pages are laid out with this correction already applied.

Saving Your Work

There are three distinct ways to save, and they solve different problems:

Option	What it saves	Best for
Save	The layout only, as a small JSON file — photos are referenced by filename, not included	Quick saves during a session on the same computer
Archive	The layout and a full copy of every photo used, bundled into one ZIP	Moving a project between computers, or long-term safekeeping
Save as Template	The layout only, with every photo reference deliberately removed	Reusing a favourite design with a completely different set of photos

Why Archive is often the better choice

A plain Save is small and fast, but it only remembers your photos by name — it depends on those exact files still being in the same folder, with the same names, whenever you come back to restore it. If you reorganise your photo library, rename files, or move to a different computer, a plain Save can leave you hunting for the right folder.

Archive avoids that problem entirely, because your photos travel inside the file itself. Restoring an archive doesn't require finding anything — everything needed is already there in the ZIP. That makes it the more genuinely reliable option, especially for a project you care about keeping long-term, or one you might want to reopen on a different computer.

The trade-off: because Archive physically includes every photo, the file size scales with your library. A project built from a few dozen photos archives to a modest file — but a project using hundreds of full-resolution photos can produce a genuinely large ZIP file, taking longer to create and more disk space to store. For very large libraries, a plain Save (paired with keeping your original photo folder somewhere safe) may be the more practical everyday choice, with an occasional Archive as a more durable checkpoint.

A reasonable approach: use Save for your regular day-to-day working file, and make an Archive once a project is finished, or before any major reorganisation of your photo folders — that way you always have one fully self-contained, future-proof copy, without paying the file-size cost on every single save.

Templates

Save as Template stores a layout with every photo reference deliberately stripped out — the design, the text, the pinned branding, but none of your pictures. Restore it later and you get that design back, empty and ready for a fresh set of photos.

From Template

🗂️⚡ From Template takes that further: it repeats the loaded template's design across as many pages as you ask for, pouring your photos into the frames as it goes.

The template's text and pinned items are preserved on every page — your fixed branding stays exactly where you put it
The image frames are reshuffled afresh on each page, so no two pages come out as identical copies
If your template contains more than one design page, they alternate (A/B/A/B…) through the run

It's the quickest way to build a long, visually consistent run of pages — a travel book, a yearbook, a catalogue — where every page should share a family resemblance without being a carbon copy of the last.

Tip: build the template once with the branding exactly where you want it, pin anything that must not move, then let From Template do the repetitive work.

Ready-made template packs to restore and build from — including film-style contact sheets — are available to download.

Restoring a Project

Use Restore to reopen a saved session. If any referenced photos aren't currently loaded, the app asks you to select the folder containing them — and if your project drew photos from more than one folder, it keeps asking, letting you load folder after folder until everything's found (or you choose to continue with gaps).

Missing photos

If some photos genuinely can't be found, the sidebar shows their exact filenames under a "Missing" heading — rather than just a bare count — so you have something concrete to search for.

If you later load or add photos that match a missing name, they're automatically placed back into their original frame, at the same crop, zoom, and rotation they had when you saved — no manual re-placing needed.

Tip: Archive sidesteps all of this, since there's never anything to go looking for — see the Saving section above.

Export & Print

Export Page and Export All save your pages as JPEG images (a ZIP of JPEGs when exporting multiple pages).

Print (labelled Save for Printing in the app) prepares your page(s) as JPEG and asks where to save them — open the saved file(s) in your photo viewer (Preview on Mac, Photos on Windows) and print from there with Cmd+P (Mac) or Ctrl+P (Windows). This two-step approach is necessary because neither platform's native app framework allows an app like this one to open a live print dialog directly, but it gives you full control over paper size and scaling through your photo viewer's own print options.

Tips for Large Photo Libraries

The app has been tested with libraries in the range of 1,000+ photos across 400+ pages, so don't hesitate to work at real scale. A few things worth knowing at that size:

Generating and exporting hundreds of pages takes real time — the progress bar reflects genuine per-page work, not a placeholder.
Photos are automatically scaled to properly fill their frame even on pages you never manually open — you don't need to click through every page before exporting.
If exporting produces a different page count than expected, the app will tell you directly rather than silently shipping an incomplete result.
Archives and multi-page exports are written straight to disk as they are built, rather than being assembled in memory first — so memory use stays low and steady however large the export becomes.

Roughly how long should this take?

Saving, Archiving, and Exporting all write to disk at a similar rate — measured at roughly 10–11 MB/s during testing. That figure is IPC round-trip overhead, not raw disk or CPU speed, so it's a reasonable planning number across different machines.

Photos in library (~6MB each)	Approx. Archive size	Approx. write time
100	600MB	~1 minute
500	3GB	~5 minutes
1,000	6GB	~9–10 minutes
1,500	9GB	~14 minutes

For Export Page, Export All, and Print, a single rendered page at 300 DPI is far smaller than a full Archive — roughly 8–16MB for A4 (2480×3508px) and 18–30MB for A3 (3508×4961px), depending on how busy the layout is. At the write speed above, that's only 1–3 seconds of actual disk time per page. For a large multi-page export, most of the total time is spent rendering each page (drawing every photo into its frame and encoding the JPEG) rather than writing it to disk — rendering speed scales with photos-per-page and your computer's processor, not disk throughput, so it isn't covered by the figures above.

Note: these figures come from real measurements on one machine and will vary with your own disk, processor, and how visually complex each page is — treat them as a rough planning guide, not a guarantee.

Troubleshooting

Red "⚠ DPI" badge on a photo

This means that photo is being stretched beyond what looks sharp at print size in that particular frame — the badge shows the approximate effective resolution. Zoom out slightly, use a higher-resolution photo, or use a smaller frame or page size.

HEIC photos not loading

HEIC/HEIF (the default iPhone photo format) requires native decoding support. macOS provides this, so HEIC/HEIF photos work normally on Mac. Windows does not, so on Windows these photos are skipped (and, when restoring an Archive, the app will tell you how many were left blank for this reason). If you're seeing HEIC photos skipped, convert them to JPEG first — most photo apps offer this as an export option.

A frame's photo looks off-centre with a border on

This was a known issue in earlier versions, now fixed — text and photo positioning both account for border thickness. If you're seeing this, make sure you're on the latest version.