"Invalid file format" is one of the most common upload errors, and it is entirely avoidable. Here is what each format is, why portals choose the ones they do, and how to convert without damaging your photo.
JPG / JPEG — the default for photos and signatures
JPG compresses photographs very efficiently, which is why portals can demand 20–50 KB files. "JPG" and "JPEG" are the same format; if a portal rejects one extension, rename .jpeg to .jpg (this rename is safe because the format is identical). Nearly every Indian exam — SSC, IBPS, NTA, UPSC and the State PSCs — asks for JPG photos and signatures.
PNG — fine for screenshots, wrong for uploads
PNG is lossless: great for screenshots and graphics, but a PNG photo is many times larger than the same JPG and is usually not accepted. Convert with PNG to JPG. Note: transparent areas in a PNG become white in JPG, which is what you want for a signature.
HEIC — the iPhone trap
iPhones save photos as HEIC by default. Most portals do not accept it, and some Windows PCs cannot even open it. Either convert with HEIC to JPG, or change the iPhone setting Settings → Camera → Formats → Most Compatible before taking your exam photo.
WEBP — the WhatsApp/browser surprise
Images saved from websites or some WhatsApp versions may be WEBP even if the name looks normal. Convert with WEBP to JPG. Better still, send yourself the original photo as a document rather than an image — chat apps recompress images and reduce quality.
PDF — for documents, not photos
Certificates, mark sheets and ID proofs are usually requested as PDF so multi-page documents stay together. Do not upload your photo as a PDF unless the notification explicitly says so. To combine scans into one file use Image to PDF or Merge PDF; to meet a size limit see compressing certificates.
Renaming is not converting
Changing photo.png to photo.jpg changes only the label. Many portals check the file's real contents and still reject it — or accept it and fail later. Always convert with a tool that re-saves the image.
Quick reference
| Upload | Usual format | If you have… |
|---|---|---|
| Photo | JPG | HEIC / PNG / WEBP → convert to JPG |
| Signature, thumb, declaration | JPG | PNG scan → convert to JPG |
| Certificates, mark sheets | PDF (sometimes JPG) | Photos of pages → Image to PDF |