Why forms prefer JPG
JPG compresses photographs far more efficiently than PNG, which is why every KB-limited form standardises on it — a photo that's 200KB as PNG might be 40KB as JPG at equivalent visual quality. PNG is built for graphics with flat colour and transparency (logos, screenshots, icons), not photographs, and it can't hit small KB targets the way JPG can.
What happens if you upload the wrong one
Some systems reject a PNG outright with a format error. Others accept it but then can't compress it small enough to pass a strict KB limit, since PNG doesn't support the same lossy compression trade-off JPG does — which is often the real reason a "file too large" error appears even after trying to shrink a PNG.
Converting safely
PixKB's Convert tab changes PNG to JPG directly in your browser. One thing to know: PNG supports transparency and JPG doesn't, so any transparent areas become solid white during conversion — expected behaviour, not a bug, and exactly what most form photos need anyway.
Frequently asked questions
Can I just rename a PNG file to .jpg?
No — renaming doesn't re-encode the actual image data, and portals that check the real file format (not just the extension) will still reject it. Use a real conversion.
Which format should screenshots use?
PNG, generally — but if a form specifically demands JPG for a document scan or photo, convert it; text usually stays legible after JPG compression at reasonable quality.