Merge Images Into a PDF Without the Hassle

You’ve got a folder of images that need to become one PDF. Maybe it’s a stack of receipts photographed with a phone, maybe it’s twelve pages of a signed contract, maybe it’s forty scans of an old photo album nobody’s touched in years. The starting point is always the same: separate image files, in order, that need to end up as a single document. The ending point should be trivial. In practice, it rarely is.

The routes people actually take

“Print to PDF” for each file, one at a time. Windows and macOS both let you print an image straight to a PDF file. It works, technically — for exactly one image. Do it forty times and you have forty separate PDFs, which is not what anyone meant by “one document.” Combining those forty afterward means reaching for a second tool anyway.

Pasting images into Word or Google Docs. This one shows up constantly, and it’s rough every time. Images get auto-resized to fit a text layout that was never designed for photos, quality visibly drops, page breaks land in the wrong place, and a ten-image document turns into twenty minutes of dragging borders around. It’s not that it can’t be done — it’s that a word processor is the wrong tool wearing a costume.

An online converter. Type “merge images to pdf” and you’ll get a dozen browser tools happy to help — right after you upload your files to their server. For a handful of harmless vacation photos, fine. For a scanned ID, a signed contract, or a photographed bank statement, you’re handing personal documents to a company you’ve never heard of, trusting a privacy policy you haven’t read, over an upload that — free tier being what it is — often comes capped at a handful of files or a size limit before it asks you to subscribe.

None of these are unreasonable things to try. They’re just the wrong shape for a job that’s genuinely simple: take these files, keep them in the order you picked, wrap them in one PDF, and don’t make it a whole afternoon.

What PDFImageMerger actually does

PDFImageMerger is a small, free, open-source desktop tool built to do exactly that one job, entirely on your machine — no upload, no account, no subscription. It runs on Linux (as a self-contained AppImage) and Windows (as a portable build), and there’s nothing to install beyond downloading the file and running it.

Here’s the workflow from an empty window to a finished PDF.

Step 1: Get your images into the app

Three ways in, pick whichever fits the moment:

• Browse to a folder and select it
• Pick individual files one at a time
• Drag and drop — files, or an entire folder, straight into the window

Once images are in, you get a list showing each one’s preview, pixel dimensions and file size — useful for spotting the one photo that’s somehow 40MB before it becomes a problem later. The list is reorderable by drag and drop, so pages photographed out of sequence (it happens more than you’d think) are a quick fix, not a redo.

Step 2: Decide how the pages should look

This is the part most “just merge them” tools skip, and it’s the part that actually matters once you look at the output:

• Page format — A4, Letter, Legal, A5, or “fit to image”, which uses no fixed page size at all: every image becomes a page exactly its own dimensions, nothing stretched, nothing cropped.
• Orientation — portrait or landscape, for the fixed formats.

If you’re merging a contract, A4 portrait is what you want. If you’re merging photographs that need to stay at their native aspect ratio, fit-to-image is the one that doesn’t quietly distort them.

Step 3: Pick resolution and compression — and see the size before you commit

Resolution (72 to 600 DPI) and compression level (low, medium, high) are the two settings that actually decide how big the final file gets. PDFImageMerger shows you an estimated final size before you build anything, calculated by actually compressing a sample of your images with the settings you picked — not a generic guess pulled out of nowhere.

That matters more than it sounds. Building a 400-image PDF only to discover it’s 300MB and too big to email is the kind of mistake you only need to make once to appreciate a tool that tells you upfront.

Step 4: Build, and be done with it

Name the file, pick a destination folder, and start the build. A progress bar tracks it, and when it’s finished you get a direct shortcut to open the PDF or the folder it landed in — no hunting through Downloads.

What actually happens to your images

This is the part worth being precise about, because “merge images into a PDF” hides a surprising amount of actual image processing underneath.

By default, PDFImageMerger normalizes what you feed it before building: EXIF rotation gets applied properly (so a photo taken sideways on your phone doesn’t end up sideways in the PDF), transparency gets flattened onto a white background, and everything gets compressed into the PDF at the quality level your DPI and compression settings imply. This is genuine image conversion, not just files being stapled together.

But sometimes you don’t want any of that — you want the exact bytes you started with, wrapped in a PDF and nothing else touched. That’s what the “don’t modify images” toggle is for. Turning it on skips the standard pipeline entirely and switches to a different path: JPEGs get embedded byte-for-byte identical to the source file (not re-encoded, not touched — the literal bytes on your disk, with EXIF rotation compensated purely through page-positioning math, since PDFs don’t read EXIF tags themselves), and anything that isn’t a JPEG goes through lossless compression instead. The result is a bigger file — lossless compression doesn’t shrink photographic noise the way JPEG does — in exchange for a guarantee that nothing about your images changed. That’s the actual trade, made explicit instead of buried in fine print.

That’s the whole tool

Add images, order them, pick a page format, pick a resolution and compression (or skip both and keep everything untouched), build. No account to create, no server involved, no subscription screen waiting at the last step.

Get PDFImageMerger on GitHub — free, open source, Linux and Windows.