Two formats cover nearly every upload field, and choosing wrong costs you either quality or file size — sometimes the upload itself, when a size cap is involved.
The one-line rule
Photographs → JPEG. Text, screenshots, line art → PNG — unless the portal names a required format, in which case the portal wins (U.S. visa photos, for example, must be JPEG).
Why
- JPEG compresses smooth gradients — skin, sky, walls — brilliantly, with a quality dial that lets a tool hit an exact size cap. Its weakness is hard edges: heavily compressed text grows “ringing” halos.
- PNG is lossless: pixel-perfect edges, ideal for screenshots and documents-as-images. Its weakness: no quality dial. A photo saved as PNG can be 5–10× the JPEG size, and if it exceeds a portal's cap there is no knob to turn — you must switch formats or shrink dimensions.
Practical answers
- Scanned paperwork with a size cap: JPEG (or a PDF containing JPEG-compressed scans). PNG scans of paper waste enormous space on paper grain.
- Screenshot of a confirmation page: PNG for fidelity — JPEG only if a size cap forces it.
- “Photo of your ID” fields: JPEG, always.
- HEIC from iPhones: convert to JPEG first; most portals don't accept HEIC.
Our Image Requirement Fixer outputs either format, and if a PNG can't meet your size cap it says so plainly and suggests the switch instead of silently failing.