Alongside the photograph and signature, a number of Indian recruitment and exam portals - IBPS among them - ask for a left thumb impression, and sometimes a handwritten declaration as well. Each has its own size rules, and each gets rejected separately.

What is usually asked for

• Left thumb impression, in black or blue ink on white paper.
• A file size typically in the region of 20-50 KB, and pixel dimensions in the same ballpark as the signature box.
• JPEG format, in almost every case.
• Clear ridges - a smudged impression is treated as invalid, and some portals warn that an unclear one can cause a candidature to be rejected later.

Your own notification is the authority. These numbers vary between organisations and change between cycles. Take the exact figures from the information handout for the exam you are applying to.

Taking a clean impression

1. Use a proper stamp pad rather than a pen. Ink from a pen fills the ridges and produces a solid blob.
2. Press once, straight down, on plain white paper. Do not roll or slide the thumb - that smears it.
3. Let it dry before touching the paper.
4. Photograph it flat, from directly above, in bright even light with no shadow across it.

Cleaning it up and resizing it

A phone photo of paper is never pure white - it is grey, slightly yellow, or shadowed at one edge, and portals notice. Run it through the Signature Background Remover first, which lifts the ink off the paper onto a clean white background, then set the exact pixel size and KB limit with the Exam Photo and Signature Resizer. Both are free, need no account, and run entirely in your browser.

If the upload is refused and you are not told why

Paste the file into Why Was My Upload Rejected? - it checks the file against the usual rules (size, dimensions, format, DPI) and names the one it breaks, rather than leaving you to guess. See also the full list of what portals check.