Turning a stack of photos into one PDF needs no app on any current platform. The feature exists everywhere and is well hidden everywhere.
The built-in route on each platform
| Device | How | Ordering |
|---|---|---|
| iPhone / iPad | Files app → select → Share → Create PDF | Filename order |
| Android | Select images → Print → Save as PDF | Selection order |
| macOS | Finder → select → right-click → Quick Actions → Create PDF | Finder sort order |
| Windows | Select → right-click → Print → Microsoft Print to PDF | Filename order |
| Any browser | JPG to PDF tool, drag to reorder | You choose |
Ordering is the recurring annoyance. Most built-in routes take the filename order, and filename order is not numeric order — IMG_10 sorts before IMG_2. If the sequence matters, rename with zero padding first, or use a tool that lets you drag the pages.
On iPhone, the option is in Files not Photos
This is why people conclude iOS cannot do it. The Photos app share sheet has no Create PDF; the Files app does.
Save the images to Files first — select them in Photos, share, Save to Files — then in Files select them all, tap Share, and Create PDF appears near the bottom of the list. Selecting a single image gives you Create PDF directly in the long-press menu.
For documents rather than photos, the Notes app is the better tool. Its scanner detects page edges, corrects perspective, cleans the background and exports straight to PDF — a considerably better result than photographing a page and converting the photo.
On Android, print is the converter
Android has no explicit Create PDF anywhere, which is why the question keeps being asked. It has something equivalent hiding behind the print dialog.
Open the images in Google Photos or the Files app, select them, choose Print from the overflow menu, then pick "Save as PDF" as the printer. The result is a PDF, one image per page, saved to Downloads.
The limitation is that this route gives you almost no control — page size, margins and scaling are whatever the print pipeline decides, and images are typically re-encoded. For a scan you intend to send somewhere official, that loss can matter. A browser-based converter that places the original image data without re-encoding avoids it.
Merging JPGs versus merging into a PDF
Two different requests share the phrase "merge JPG files", and they have different answers.
One PDF with several pages is what most people want — each image becomes a page, and the result is a document. Any of the routes above does it.
One image containing several images is a collage or a vertical stitch — a single JPG, not a document. That is an image-editing job, and the output cannot be paginated or searched.
If the destination is a form upload, a printer or an email attachment, you want the PDF. Multi-page images exist as TIFF but almost nothing outside document scanning handles them, so a PDF is the safer choice even when the content is purely photographic.
Adding an image to a PDF that already exists
Inserting a signature graphic, a logo or a photo into an existing document is a different operation from building a PDF out of images, and the free tooling is thinner.
The reliable options are placing the image as an annotation, or converting the page to an editable form and back. Preview on macOS does the first natively — copy an image, open the PDF, paste, then drag and resize. Adobe Reader does not allow it without a subscription, which is why the question comes up so often on Windows.
- A signature: use a signing tool. Sign PDF places a drawn or uploaded signature and flattens it into the page.
- A watermark or logo on every page: a watermark tool, which repeats the placement across the document.
- A one-off image on one page: Preview on macOS, or LibreOffice Draw on any platform — it opens PDFs and lets you place images directly.
- An image as a new page: build a one-page PDF from the image and merge it in.
That last approach is the most robust and the least obvious. Making the image its own PDF and merging avoids editing the original page content at all, which means nothing else in the document can be disturbed.
Keeping the file a sensible size
A PDF of twenty phone photos is easily 60 MB, because a current phone camera produces 3–5 MB per shot and the PDF stores each one whole.
That is fine for archiving and too large for email or most upload forms. The fix is resolution rather than compression: a photo at 4000 pixels wide contains far more detail than a printed or on-screen page can show.
Resize the longest edge to around 2000 pixels before building the PDF and the file typically drops by three-quarters with no visible difference on screen or in print. Image Compressor and Image Resizer both run in the browser, so holiday photos and scanned documents alike stay on the machine.
Frequently asked questions
How do I turn JPGs into a PDF on iPhone?
In the Files app, not Photos — that is why it seems missing. Save the images to Files, select them all, tap Share, and choose Create PDF near the bottom of the list. A single image offers Create PDF directly from its long-press menu.
How do I convert JPG to PDF on Android?
Through the print dialog. Select the images in Google Photos or Files, choose Print from the overflow menu, then pick "Save as PDF" as the printer. There is no dedicated Create PDF option on Android, which is why the feature is hard to find.
Why are my images in the wrong order?
Most built-in routes use filename order, which is alphabetical rather than numeric — IMG_10 sorts before IMG_2. Rename with zero padding (01, 02, 03) or use a converter that lets you drag pages into position.
Is PNG to PDF different from JPG to PDF?
Only in what is preserved. PNG is lossless and supports transparency, which PDF renders against a white background. For screenshots and diagrams PNG is the better source; for photographs JPG is smaller with no visible difference.
How do I insert an image into an existing PDF?
On macOS, copy the image and paste it into the PDF in Preview, then drag to position. On any platform, LibreOffice Draw opens PDFs and places images directly. For a signature, use a signing tool. To add an image as a new page, build a one-page PDF from it and merge — that leaves the original pages untouched.
Why is my image PDF so large?
Phone photos are 3–5 MB each and the PDF stores them whole. Resize the longest edge to about 2000 pixels before converting — that is more than enough for screen and print, and typically cuts the file by three-quarters.
Should I scan documents with the camera or a scanner app?
Use a scanner app. The iPhone Notes scanner and Android equivalents detect page edges, correct perspective and clean the background, producing a far more legible document than a photograph of a page converted to PDF.