Screenshots are text, so they are written without loss
A screenshot of a payment confirmation, a chat or a web page is mostly letters on flat colour. Turned into a PDF the usual way, it is re-compressed as a photograph, and every letter grows a faint grey fringe. On this page the screenshot’s pixels go into the PDF without loss — Flate-compressed samples rather than JPEG — at exactly the resolution they were captured at.
A worked example: a 1080 × 6400 pixel scrolling screenshot became five A4 pages at full width, each written losslessly, in a PDF of 48,009 bytes — the screenshot’s own pixels, smaller than most JPEG versions of it would be because flat colour compresses so well.
Long screenshots keep their width
A scrolling screenshot from a phone can be ten times taller than it is wide. Shrunk onto one A4 page, it becomes a thin column of text too small to read. Here a screenshot that is much taller than the page keeps the page’s full width and continues onto the next page, and the next, like a long receipt fed through a printer. Each page repeats a sliver of the one before at its top edge, so a line that falls on a join appears whole on one side of it. The storyboard shows every page before you save, and if you would rather have one page per screenshot, switch it off on the Pages step.
Size, honestly
Lossless pages are larger than JPEG pages. A size target never turns a lossless page into JPEG on its own; if you need the file under a limit, switch Lossless pages off on the Quality step and the builder will compress them, measuring as it goes. For a mix of photos and screenshots, PNG to PDF and image to PDF take any format, and the size-limited builder takes any figure.
Questions about screenshots to PDF
What happens to a very long screenshot?
It keeps the page's full width and carries on onto as many pages as it takes, instead of being shrunk into one unreadable strip. A sliver at the bottom of each page is repeated at the top of the next, so no line of text is cut in half. Turn this off on the Pages step to fit each screenshot on one page instead.
Why are the pages lossless?
Screenshots are text and flat colour, which JPEG compression smears into grey halos around every letter. Lossless pages keep exactly the pixels of the screenshot, compressed without loss. The file is larger than a JPEG one; switch Lossless pages off on the Quality step if size matters more.
Are my screenshots uploaded?
No. Screenshots often hold chats, bank details and passwords, and here they are laid out and written into the PDF by this browser. Nothing is sent.
What does the PDF contain?
Your screenshots as images. Text in them is pixels, not selectable text, and there are no file names, no metadata and no title unless you type one.
Can I paste a screenshot instead of saving it first?
Yes. Copy a screenshot and press Ctrl+V (⌘V on a Mac) anywhere on this page outside a text field, and it joins the document.