This is the commonly used size: we found no requirement published by the institution. Confirm it before your application.
Tips to get it right the first time
Colour photo in JPEG; the portal shows the exact size limit before you upload, so check it there.
If you have Aadhaar linked to your mobile, the Instant e-PAN on the Income Tax portal is free and needs no photo.
The signature is uploaded separately: sign on white paper with a dark pen and scan only the signature.
How to do it with Requisito Listo
Open the «PAN card photo» template in the app.
Take the photo with the on-screen guide (or pick one from your gallery).
The app centers your face, makes the background white and gets the exact size and file weight.
Check the checklist, then upload or save it.
At the end you'll see a checklist: size, file weight, background and format. If something doesn't comply, it tells you what to fix before the portal rejects it.