Images to PDF

The document will be about as large as your images

Because nothing is recompressed, twenty 4 MB photos make an 80 MB PDF. That is the honest trade for not degrading them, but it is often more than anyone needs — a document to be read on screen or emailed rarely benefits from full camera resolution.

If size matters more than maximum quality, compress the images first and then build the PDF. Compressing at quality 80 typically takes 60–80% off with no visible change at document scale, and the PDF inherits the saving directly.

The same applies to resizing. An image wider than about 2500 pixels gains nothing on an A4 page at print resolution.

PNG photos make very large documents

A photograph saved as PNG is often ten times the size of the same photo as JPEG, and the PDF carries that straight through. If your images are photographic PNGs, convert them to JPG first — at a high quality the difference is invisible and the document is a fraction of the size.

Keep PNG for screenshots, diagrams and anything with text or sharp lines, where lossless genuinely matters.

Transparency becomes white

A PDF page is a sheet of paper, so transparent areas show as white. For screenshots and scans that is exactly right. Semi-transparent areas are preserved as a soft mask, so a shadow fades rather than developing a hard edge.

What people use this for

• Photographed documents — a contract or form snapped page by page and submitted as one PDF, which is what most systems accept.
• Receipts and expenses, combined into one attachment per claim.
• Scanned pages from a phone scanner app that saved images.
• Portfolios and proofs sent as a single file rather than a folder.
• Screenshot walkthroughs, where order is the entire point.
• Anywhere the upload accepts PDF only, which is a large share of the reason anyone does this.

Order is the part to take care over

Page order is the only thing here that cannot be fixed after the fact without rebuilding, so the list is the biggest thing on the page: rows drag, arrows work when dragging is awkward, and page one is at the top.

Images are added in the order you select them and are never sorted by filename. That sounds unhelpful and is deliberate — IMG_1002 sorts before IMG_998 alphabetically, which is the opposite of the order they were taken in, and a document silently assembled in that order is worse than one you arranged yourself.

This does not make your text searchable

Worth being explicit, because it disappoints people regularly. A photograph of a page becomes a picture of a page. The PDF contains an image, not text, so you cannot search it, select from it, or copy out of it.

Turning pictures of words into words requires optical character recognition, which is a different kind of tool. If a system needs a searchable document, a PDF built from photos will not satisfy it however tidy it looks.

Your images are uploaded, and here is what happens to them

The PDF is built on our server: browsers cannot write PDF documents, and there is no way around that in a page.

So: your images are uploaded over an encrypted connection, the document is built, and every uploaded image is deleted the moment the build finishes — including when it fails. The finished PDF is reachable only through a signed link that expires, and is deleted once you download it. The images themselves are never kept, logged or inspected; if a build fails, we record how many images there were and the error — not the images.

If you would rather nothing left your device at all, build the document with a desktop application instead. That is a reasonable thing to want for sensitive papers, and it is better to say so than to imply a privacy this particular tool cannot offer.

One image, or several?

For a single image, JPG to PDF and PNG to PDF do the same job with fewer controls. Use this when there is more than one and the order matters.

And if you want the images side by side on one page rather than one page each, that is merging, not a PDF — merge them first, then convert the result.