PNG, WebP, AVIF and iPhone HEIC in. Clean JPG out, at whatever file size your form demands.
Application portals almost universally want JPG. Modern phones almost universally do not produce it by default — iPhones shoot HEIC, screenshots are PNG, and shared images increasingly arrive as WebP. That mismatch is behind a large share of “invalid file format” errors.
What changes when you convert to JPG
- Transparency is flattened. JPG has no alpha channel, so transparent areas of a PNG are filled with white. For a signature scan that is exactly what you want.
- The file usually gets smaller. JPG compresses photographs far more efficiently than PNG, often by 80% or more on a camera image.
- Text and line art get slightly softer. JPG is built for photographs. A screenshot of a table will look marginally fuzzier as a JPG than as a PNG — acceptable for form uploads, not ideal for archiving.
About iPhone HEIC files
HEIC is Apple’s default camera format. Safari on a recent iPhone can decode it in-page, so the converter above usually handles it directly. On Windows and Android, browser support is inconsistent and the file may not open at all.
The reliable fix is on the phone: Settings → Camera → Formats → Most Compatible makes the camera shoot JPG from then on. For photos you have already taken, open one in Photos, tap Share, and choose Mail or Copy Photo — iOS converts to JPG on the way out. Then bring that file here.
Convert and size in one step
Tick the file size box and the converter compresses to your ceiling as it converts, so you do not need a second pass. If the form wants a minimum instead, convert here first, then increase the size in KB.
Frequently asked questions
How do I convert PNG to JPG?
Upload the PNG, leave the format set to JPG, and download. Any transparent areas are filled with white, which is what application portals expect.
Can I convert HEIC to JPG?
On an iPhone or Mac, usually yes — Safari can decode HEIC directly. On Windows or Android the browser often cannot read the format. In that case set your iPhone camera to Most Compatible, or share the photo through Mail to get a JPG copy.
Does converting to JPG lose quality?
A little, once. JPG is lossy, so the first save discards some detail — imperceptible at normal quality settings on a photograph. Avoid converting back and forth repeatedly, since each round trip loses a bit more.
Is the conversion done on a server?
No. It runs in your browser. The file is never transmitted, which matters when the image is an ID document or a signature.