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By Sakshi • • 8 min read

Exam Photo & Signature Sizes: How to Read the Rules

Recruitment portals constrain your photo along four axes at once. Miss any one and the upload fails. Here's how to decode the requirement and satisfy it in one pass.

Application portals for bank exams, civil service recruitment, railway boards and university admissions all specify photo uploads in roughly the same way — and the specification is genuinely harder to satisfy than it looks, because it constrains four separate properties simultaneously.

Always verify against your own notification. Requirements change between recruitment cycles, and two exams run by the same body can differ. Treat any figure you find online — including on this page — as a guide to what the rules look like, then confirm it against the official notice or the instruction text on the upload page itself.

The four constraints

Nearly every photo requirement is some combination of these. Reading them out of the notice before you touch an editor saves a lot of retries:

  1. Pixel dimensions — often given as a range ("between 200×230 and 400×460") rather than an exact figure.
  2. File size — usually a maximum, very often also a minimum. The floor is the one people miss.
  3. Format — almost always JPEG. Some legacy portals still ask for BMP.
  4. Content rules — plain light background, face proportion, recency, no headwear, eyes visible, signature in black ink on white paper.

The fourth category is the one no resizing tool can fix for you. If the notice says the photograph must be taken within the last three months against a white background, that's a camera problem, not a software problem.

Photos and signatures are different problems

These get lumped together in the instructions, but they behave very differently under compression and deserve separate treatment.

Photograph

A portrait is continuous-tone data: skin gradients, hair detail, soft background. It has a lot of information in it, so it compresses reasonably but degrades visibly when squeezed too hard. Typical limits are generous enough — 20 KB to 50 KB at a few hundred pixels square is comfortable.

Signature

A signature is mostly flat white with thin dark strokes. That compresses extremely well, which is why signature limits can be as tight as 1–15 KB. The risk is the opposite one: it's easy to land under a minimum, and easy to lose thin strokes entirely if you scan at low resolution.

Order of operations

The sequence matters more than the tool. Doing these steps out of order is the most common reason people end up fighting the same file for twenty minutes.

Step 1 — Crop to the required ratio

Before anything else. If the target is 200×230, that's a 20:23 ratio, and no amount of resizing will get you there from a 4:3 phone photo without distortion. Crop first, framing the face as the notice describes.

Step 2 — Set the pixel dimensions

If the requirement is a range, aim at the upper end. More pixels give the compressor more to work with and look better on a printed admit card. If it's an exact figure, use it exactly.

Step 3 — Choose JPEG

Do this before compressing, because format determines what compression is even possible. PNG ignores quality settings entirely — you cannot hit a KB target with it. If the portal wants BMP, note that BMP is uncompressed and file size follows directly from dimensions.

Renaming will not work here, and this is a common way applications fail. A file's real format lives in its first few bytes, not in its extension, so a PNG or an iPhone HEIC saved as photo.jpg is still a PNG or a HEIC and a portal that reads the header will reject it. The file has to be genuinely re-encoded as JPEG — which is what choosing JPEG here does.

Step 4 — Compress to a target inside the range

Aim for the middle, not the ceiling. For a 20–50 KB window, target 40 KB. You clear the minimum comfortably and leave headroom for the KB-versus-KiB ambiguity that bites people sitting exactly on the limit.

Step 5 — Look at the file you downloaded

Not the preview — the actual downloaded file. Check the background didn't turn black, the photo isn't rotated, and the face is still legible. Two seconds here beats a rejected application.

In our resizer, steps 2 to 4 happen in a single pass: set the dimensions, pick JPEG, tick compress to target file size, enter your number, and download once. You don't need to chain three separate tools together, and the image is only re-encoded once — each extra round trip through a lossy encoder throws away a little more detail.

Compress to an Exact KB Size →

Scanning a signature properly

Signature uploads fail more often than photos, usually for reasons that trace back to how the signature was captured rather than how it was resized.

  • Sign on unlined white paper with a black or dark blue pen. Ruled lines survive compression and look like part of the signature. Most notices specify black ink; some accept blue.
  • Capture in even light, not with flash. Flash creates a bright hotspot and a gray gradient across the page. That gradient is continuous-tone data, which inflates file size dramatically — the exact opposite of what you want at a 15 KB limit.
  • Crop tight to the strokes. Every millimeter of blank paper is pixels spent on nothing. A tight crop at the same file size means more detail where it matters.
  • Keep the background genuinely white. A phone photo of white paper is usually light gray. Compression handles flat white far better than mottled off-white, so this materially affects whether you can hit a tight target.
  • Respect the aspect ratio, but check it first. Signature fields are usually wide and short — something like 140×60 pixels — and a square crop of a wide signature gets squashed. Do not assume it, though: UPSC asks for three signatures signed one below the other and scanned as a single image, which is a tall image rather than a wide strip, at 20–100 KB. Guides that list a single "3.5 × 1.5 cm" signature size for every Indian exam get UPSC wrong.

If you're stuck above a tight limit, reduce dimensions before reaching for more compression. A signature is one of the few images where quite small pixel dimensions genuinely look fine.

When you can't hit the target

Sometimes a target is unreachable at your current dimensions. That isn't a tool failure — it's arithmetic. A JPEG has a floor below which it cannot represent that many pixels, and pushing past it produces blocky artifacts rather than a smaller file.

The fix is always the same: reduce the pixel dimensions, then compress again. If the notice gives a dimension range, move toward the lower end of it. If it gives an exact size that you genuinely cannot meet within the file-size limit, re-read the notice — it's likely the limit applies to a different upload field than you think.

Our tool tells you when it couldn't reach a target rather than handing back an oversized file and letting the portal reject it. That's deliberate: a clear failure is more useful than a silent one.

A short pre-submission checklist

  1. Photo and signature are separate files, each meeting its own rules.
  2. Both are genuinely JPEG — re-encoded, not renamed.
  3. Each file sits inside its range, not on either boundary.
  4. Dimensions match the required ratio without stretching.
  5. Backgrounds are light; nothing turned black in conversion.
  6. Neither file is rotated after upload preview.
  7. You kept the originals, in case a later stage wants a larger version.

That last point is worth emphasizing. Many processes ask for a small photo at application time and a larger one at document verification. Keep your full-resolution original — compressing to 15 KB is a one-way door.

Set dimensions, format and file size in one pass

Open the image resizer →

Your photo never leaves your device — all processing runs in your browser.

Common target sizes

Direct links to the file sizes portals ask for most often:

Also useful: why a correctly sized photo still gets rejected, and passport photo dimensions by country.

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