Advice about exam photo sizes is full of guesses. We wanted numbers, so we measured them with the same tools this site runs. This page lists every result and exactly how we got it, so you can judge it yourself.
How we measured
- Photos: 6 colour portraits: the project's own test photo (a public-domain official portrait) and 5 openly licensed portraits from Wikimedia Commons, with different backgrounds (plain walls, a busy office, outdoors, a phone selfie). The list of files is kept with the test script.
- Tool: each photo was cropped and resized by ExamFitr's own editor using an exam preset, exported losslessly, then encoded with Chrome 151.0.7922.169's JPEG encoder at each quality. This is the same encoder the editor uses.
- Quality measure: PSNR (peak signal-to-noise ratio) against the lossless crop. Higher is closer to the original; above about 40 dB differences are hard to see at normal viewing size.
- Date: measured on 2026-10-03. Results from other encoders (phone apps, Photoshop) will differ somewhat. The raw data and CSV downloads are on the benchmark data page.
- Privacy check: the run made 389 network requests, 0 to third parties and 0 with a request body. Nothing was uploaded.
1. JPEG quality vs file size
Median file size over the 6 photos at four common quality settings. The full table, with minimum, maximum and PSNR at every quality from 50 to 100, is on the benchmark data page.
| Photo size | Quality 80 | Quality 90 | Quality 95 | Quality 100 |
|---|---|---|---|---|
| 200 × 230 px | 9.1 KB | 12.8 KB | 17.8 KB | 47.7 KB |
| 350 × 450 px | 23 KB | 33.4 KB | 47.5 KB | 142.8 KB |
| 550 × 550 px | 36.8 KB | 54.8 KB | 80.3 KB | 257.1 KB |
What it shows: file size roughly doubles between quality 80 and 95, then jumps about three-fold from 95 to 100 for almost no visible gain. The spread between photos is large: the busiest photo is often twice the size of the plainest at the same quality, so "quality 80 gives 20 KB" is never true for every photo. A 20–50 KB limit at 200 × 230 px allows quality 95 or higher for all six photos.
2. How heavy can a small signature get?
A cleaned phone photo of a signature (dark ink on white), resized by the editor's presets and encoded at high qualities:
At quality 100, the largest it got was 5.6 KB at 140 × 60 px, 12.1 KB at 276 × 118 px, 16.3 KB at 350 × 150 px and 19.3 KB at 472 × 157 px (all values).
What it shows: at 140 × 60 px no quality setting reaches the 10 KB minimum in IBPS-format forms, and at 276 × 118 px none reaches NEET PG's 20 KB. This is why the editor pads JPEGs up to a minimum instead of distorting the image (see minimum KB limits).
3. Does a white background make the file smaller?
Each photo was cropped to 350 × 450 px, then its background was replaced with white using the editor's background tool ("Best" model, running in the browser). We compared the file size at fixed qualities, and the highest quality that fits under 50 KB. The per-photo results are on the benchmark data page.
What it shows: the median saving was 16.6% at quality 80 and 17.4% at quality 92. The three photos with busy backgrounds (an office, a living room, trees) shrank by 31–44%. The other three barely changed: one was already against a plain pink wall, one against a plain grey wall, and one was a close selfie where little background was left after cropping. Removal took about two seconds per photo on our test machine. That is a CPU-only server, so a typical laptop may be faster or slower.
Practical takeaways
- Set the exact pixels first, then aim just under the maximum KB. Most exam limits allow quality 90 or more.
- Don't chase quality 100: it triples the file for no visible gain.
- Small signatures can't reach some minimums on their own; padding is the honest fix.
- A plain background helps a tight limit, but only where the exam asks for one.
Read the practical guide: keeping a compressed photo sharp.