Resolution: from pixels to inches
A PDF page has a size in points, and a point is 1/72 of an inch. A picture of the page has a size in pixels, and the resolution connects the two: pixels equal inches times dots per inch (DPI). An A4 page is 8.27 by 11.69 inches, so at 150 DPI it is 1240 by 1754 pixels. The tool shows this number before you convert, so you can see what you will get.
- 72 DPI: 595 by 842 pixels for A4. Small, and fine for thumbnails and previews.
- 96 DPI: 794 by 1123 pixels. The size of an A4 page on a web page at 100 percent zoom.
- 150 DPI (default): 1240 by 1754 pixels for A4, and 1275 by 1650 for US Letter. Sharp on screens and easy to read.
- 200 DPI: 1654 by 2339 pixels. Good for presentations and for zooming in.
- 300 DPI: 2480 by 3508 pixels. The usual choice for printing and for programs that read text from pictures. It has four times the pixels of 150 DPI, so the files are much bigger.
Browsers limit how large a picture can be. This tool draws a page up to about 67 million pixels on a computer and about 16.7 million on a phone or tablet, and never wider or taller than 16,384 pixels. A page beyond that, such as a poster or a large map, is drawn at a lower resolution. The panel says so before you convert when the first chosen page is affected, and the result lists every page that was drawn lower, with the resolution it got. Nothing is shrunk without telling you.
PNG, JPG or WebP
PNG keeps every pixel exactly and is the best choice for pages with text, lines and flat colour, such as documents, slides and diagrams. It can have a transparent background. Its files are the largest. See PDF to PNG.
JPG makes much smaller files and suits pages that are photos or scans. It always has a white background, and at low quality it leaves faint blocky marks around text. The quality slider starts at 90. See PDF to JPG.
WebP is usually smaller than both and can be transparent. Browsers and modern apps open it, but some older programs do not. The quality slider starts at 85, and a WebP picture cannot be more than 16,383 pixels wide or tall.
Pages, file names and downloads
Pick pages in the grid or in the box, whichever is easier. Typing 2-4, 9 ticks pages 2, 3, 4 and 9 in the grid, and ticking in the grid updates the box. The pages are drawn in the order of the PDF, and the result list keeps that order.
Files are named after the PDF, then the page number, padded with zeros to the width of the page count so they sort correctly: a PDF called report.pdf with 12 pages gives report-page-01.png to report-page-12.png, and with 300 pages it gives report-page-001.png onwards. A single page downloads as one picture. Several pages are shown in a list with a small thumbnail, the size in pixels and bytes, and a download button for each, and Download all as ZIP packs them into one file named after the PDF.
The pages are drawn one after another and each one is released before the next, so a PDF with hundreds of pages does not need more working memory than one with a few. What does add up are the finished pictures, which are held until you download them. The tool warns before a job that is likely to produce several hundred megabytes.
What changes when a page becomes a picture
A picture holds pixels, not letters. The text is no longer text: you cannot select, search or copy it, and links and bookmarks are gone. If you want the words, use PDF to Text. Comments, stamps and form fields are drawn the way the PDF reader built into this page draws them, which is PDF.js, the reader inside Firefox. They can differ a little from Acrobat or Preview.
A scanned PDF is made of pictures already, so converting it gives you those pictures back at the resolution you chose. A higher resolution than the scan has adds pixels but no detail. ClipLime does not read text from pictures. PDFs protected with a password or with permission settings cannot be converted.