How to combine multiple images into one PDF
Turning a stack of photos or scans into one PDF is one of those tasks everyone needs occasionally and nobody remembers how to do. Every operating system can do it, none of them makes it obvious, and the settings that matter aren't the ones you're offered first.
Here's how to do it wherever you are, and what the settings actually change.
Why PDF at all?
A PDF holds multiple pages in a fixed layout, opens identically on every device, and is the format almost every institution expects for documents. When someone asks for "a scan of your ID and proof of address", they want one PDF, not four JPGs — and email clients and web forms often reject multiple attachments anyway.
The other reason: page order. Images in a folder sort alphabetically, which is rarely the order you want. A PDF fixes the sequence permanently.
In your browser (any device)
A browser-based tool is the fastest route if you're not on your own computer, and the only one that works identically on a phone, a laptop and a work machine where you can't install anything.
Drop the images in the order you want them, choose a page size, download. The one thing to check is whether the tool uploads your files — for ID documents, contracts or anything sensitive, that matters. You can test it by disconnecting from the internet and seeing whether it still works.
On Windows
Using Print to PDF (built in, no software needed):
- Open File Explorer and select your images. The selection order matters — click them in the sequence you want, or rename them
01,02,03first. - Right-click → Print.
- In the Printer dropdown choose Microsoft Print to PDF.
- Pick a layout on the right — Full page photo for one image per page.
- Click Print, and choose where to save.
That's it. The quirk is that ordering depends on selection order or filename, and the Photos app sometimes overrides your quality settings. If the result looks soft, that's why.
On macOS
Using Preview:
- Select all images in Finder, right-click → Open With → Preview.
- In Preview's sidebar (View → Thumbnails), drag them into the order you want.
- Select all thumbnails (Cmd+A).
- File → Print, then click the PDF dropdown at the bottom-left → Save as PDF.
Alternatively, select the files in Finder, right-click → Quick Actions → Create PDF. That's faster but gives you no control over page size or order beyond the filename sort.
On iPhone and iPad
From the Photos app:
- Select your photos → tap Share → Print.
- On the print preview, pinch outward on the preview image.
- It becomes a PDF. Tap Share again to save or send it.
That pinch gesture is genuinely undiscoverable, and it's how millions of people make PDFs on iOS.
Or use the Files app: put images in a folder, tap ⋯ → Select, select them, then ⋯ → Create PDF.
For actual documents, use Notes instead: new note → camera icon → Scan Documents. It detects edges, corrects perspective and produces a far better result than photographing a page flat.
On Android
Most Android phones can do it from the Files app or Google Drive: select images → ⋮ → Print, then choose Save as PDF.
For documents, Google Drive → + → Scan does edge detection and multi-page capture, and saves straight to a PDF.
The settings that actually matter
Page size
- A4 or US Letter — use for anything you'll print or submit. A4 is standard everywhere except the US and Canada.
- Fit to image — the PDF page becomes exactly the image's dimensions, with no white margin. Ideal for photos, screenshots and receipts that will only ever be viewed on screen. It looks odd if printed.
If a form specifies A4, use A4. Institutions do reject documents on the wrong page size.
Orientation
Auto-orientation picks portrait or landscape per image based on its shape, which is usually right. Force one only if you need every page consistent.
Margins
Zero margins look clean on screen but risk being clipped by printers, which usually can't print to the very edge. 10–20 points (roughly 4–7 mm) is a safe margin for anything that might be printed.
Quality — the setting that decides your file size
Images inside a PDF are compressed, usually as JPEG. This single number is the difference between a 400 KB file and a 15 MB one:
| Quality | Result | Good for |
|---|---|---|
| 95–100 | Near-lossless, large files | Photo portfolios, print submission |
| 85–90 | Visually identical for most content | The sensible default |
| 70–80 | Slight softening on close inspection | Email attachments, forms with size limits |
| Below 70 | Visible artefacts, especially on text | Only when you must hit a hard limit |
Most upload forms cap attachments at 2 MB, 5 MB or 10 MB. If you're over, drop the quality before you start deleting pages.
Getting scans right
If the images are photographs of documents rather than flatbed scans, a few things make a large difference:
Light it evenly. Diffuse daylight beats a ceiling light directly overhead, which casts your own shadow across the page. Avoid flash — it produces a bright hotspot in the middle.
Shoot straight down. Angled photos produce keystoned pages that look unprofessional and can fail automated document checks. Phone scanning apps correct this automatically, which is why they're worth using.
Crop tightly. Nobody needs to see your desk.
Use a scanner app for documents. Notes on iOS, Drive on Android. They handle edges, perspective and contrast in one step and produce something that looks like a scan rather than a photo of paper.
Check orientation before combining. A sideways page is far more annoying to fix after the PDF exists than before.
Common problems
Pages are in the wrong order. Rename the files 01-, 02-, 03- before you start. Alphabetical sorting puts 10 before 2, which is the usual culprit.
The PDF is enormous. You're embedding full-resolution phone photos at high quality. Resize to about 1600–2000 pixels on the long edge first, and use quality 85. A five-page document has no business being 40 MB.
Transparent PNGs have black backgrounds. PDF pages don't support transparency the way PNG does, so transparent areas need filling. Choose white in your tool's background setting.
The text in my scan is blurry. Usually the source photo, not the PDF. Re-shoot with better light and a steady hand, or use a document scanner app.
It's rejected by an upload form. Check three things: file size limit, page size (A4 vs Letter), and whether they asked for a single file rather than several.
A note on privacy
The documents people most often turn into PDFs — ID cards, bank statements, contracts, medical letters — are also the ones you'd least like sitting on a stranger's server. Every operating system above can do this entirely offline, and browser-based tools that process locally can too.
For anything with your name, address, signature or account numbers on it, that's worth thirty seconds of thought before you drag it into the first search result.