PDF to JPG

A PDF is not really an image; it is a programme for drawing pages. To convert it to JPG or PNG, the tool has to actually run that programme: load each page, render the fonts, draw the vector shapes, paste in the embedded images, and capture the result as a bitmap. The tool above uses pdf.js, the same Mozilla rendering engine that powers Firefox's built-in PDF viewer, so what you see in the export matches what the file looks like on screen.

The scale setting controls render resolution. 1x produces an image at the page's native size (roughly 72 DPI), which is fine for previews. 2x doubles the linear dimensions for sharper output (about 144 DPI), and 3x or 4x is closer to print quality. Higher scale means longer render time and bigger files; for a typical screen-shared image, 2x JPG at 80% quality is a good default.

JPG uses lossy JPEG-DCT compression, the same algorithm as your phone camera. It is excellent for photographs and complex artwork, where small compression artefacts blend into the noise of the image. File sizes are small, but you cannot reduce quality and recover detail later.

PNG uses lossless Flate compression. It keeps every pixel exactly, which makes it the right pick for screenshots, line drawings, scans of text, or anything with sharp edges. PNGs of text-heavy pages stay crisp; JPGs of the same pages tend to develop visible halos around letters, especially at lower quality settings. Choose PNG if the rendered page contains mostly text or vector graphics.

Rendering happens entirely in your browser using pdf.js. The original PDF is never sent to a server, and neither are the resulting images. That is the right model for converting confidential PDFs to images: solicitor's letters, salary slips, NHS correspondence. Free online converters that upload to a server log every conversion they do.

Mobile browsers will struggle with very long PDFs at high scale settings. A 100-page document at 4x scale generates around 100 large bitmaps in memory simultaneously. If you hit a wall, drop the scale or use [Split PDF](/split-pdf) to break the file into chunks first. For the reverse conversion, [JPG to PDF](/jpg-to-pdf) bundles images back into a single document.