convert pdf diagram to png

JPG compression works by approximating blocks of similar-looking pixels, which is efficient for photographic content with smooth gradients but tends to introduce visible ringing or blurring around sharp, high-contrast edges — exactly what text characters, thin lines, and diagram boundaries are made of. A diagram exported as JPG at a moderate-to-low quality setting can show fuzzy text edges or slightly blurred connector lines that weren't there in the original PDF page.

PNG avoids this entirely because it doesn't approximate anything — every pixel in the export matches the rendered page exactly. For a flowchart, a technical diagram, a UI screenshot embedded in a PDF, or any page where small text and precise lines carry the actual information, PNG is the format that won't quietly degrade that content during export.

The trade-off is file size, though it's less punishing for this specific kind of content than you might expect: diagrams and line-art pages tend to have large areas of flat, uniform color (white backgrounds, solid-color shapes), which PNG's lossless compression handles efficiently even without approximating anything — so the size penalty versus JPG is often smaller here than it would be for a busy photographic page.

If you're exporting a diagram specifically to zoom in and read fine text or labels later, PNG is the safer choice for that reason alone — you won't discover compression artifacts obscuring a label only after you've already relied on the JPG version.