If you've ever tried to upload a photo to a government exam portal and gotten an error saying only JPG or JPEG files are accepted, you've run into one of the most common, and most misunderstood, format restrictions on Indian application forms. Here's what actually separates JPEG from PNG, and why almost every exam body insists on JPEG specifically.
It's a simple technical distinction once you see it clearly, and understanding it will save you a repeat trip through the upload page the next time a form rejects your file for no reason you can immediately spot.
The Real Difference Between JPEG and PNG
JPEG, also written JPG, is a lossy, compressed image format - it discards a small amount of picture data each time it's saved, in exchange for a much smaller file size. That's exactly why a JPEG photo can be squeezed down to 20-100 KB while still looking sharp enough for identification purposes. PNG, on the other hand, is a lossless format - it preserves every pixel exactly, which makes it excellent for screenshots, logos, and graphics with sharp edges or transparency. But that also means PNG files are typically several times larger than a JPEG of the same photo, often too large to fit inside a 100 KB limit without a steep drop in resolution.
Transparency is the other big PNG feature, and it's worth calling out because it's completely irrelevant here: PNG can save an image with a see-through background, which is useful for logos placed over different colored pages, but a photo of a person or a signature is always going to sit on a solid background anyway, so that capability adds file size for a form upload without adding any real benefit.
Why Government Forms Specifically Ask for JPEG
For a passport-style photo or signature, none of PNG's strengths actually matter: ID photos don't need transparency, and they don't need pixel-perfect, lossless detail - they need to be small, quick to upload, and consistent across the millions of applications a portal like RPSC, WBPSC, SSC, or UPSC processes every recruitment cycle. JPEG's compression is built exactly for photographs like this, so it became the de facto standard, and most exam bodies simply state JPEG/JPG only in their guidelines rather than supporting multiple formats and the extra server load that comes with them.
There's also a practical server-side reason: when a recruitment portal has to store and process lakhs of applications, keeping every uploaded image in a small, predictable file size range makes the whole system faster and cheaper to run, which is another reason exam bodies standardize tightly on one compressed format instead of accepting whatever format each applicant happens to have.
What Happens If You Upload a PNG by Mistake
Most government portals will either reject a PNG file outright with an error message, or in rarer cases, let it upload but flag the application for manual correction later, which can delay processing. Since many phone screenshots and some scanner software save as PNG by default, it's worth checking your file extension before you upload - if it ends in .png, convert it to .jpg first. SignResizer.com automatically outputs a properly compressed JPEG regardless of what format you upload, so you don't have to remember to convert it yourself.