RRB Railway Photo and Signature Size 2026 — Group D, NTPC, ALP Guide
Railway recruitment drives are some of the biggest in India — the RRB Group D notification alone attracts crores of applicants. And yet, one of the most common reasons for application trouble is something as basic as the photo and signature upload. The RRB portal is notoriously picky about file specifications, and the error messages it gives you are about as helpful as a blank screen.
RRB Photo Specifications for 2026
For Railway RRB exams (Group D, NTPC, ALP, Technician, RPF), the photo requirements are: 35 mm x 45 mm dimensions, which is about 413 x 531 pixels at 300 DPI. File size should be between 15 KB and 40 KB. Format must be JPEG/JPG. Background should be white or a very light colour.
RRB Railway Photo — Quick Specs
Dimensions: 35 × 45 mm (~413 × 531 pixels)
File size: 15 KB to 40 KB
Format: JPEG/JPG only
Background: White
Signature: ~140 × 60 px | 10–20 KB
Left thumb: Required for some exams
Notice that the upper limit is just 40 KB — tighter than SSC's 50 KB limit. This means you need to be more aggressive with compression, but not so much that the photo becomes grainy. The 15-40 KB window gives you only 25 KB to work with, so precision matters here.
Signature and Left Thumb Impression
The signature should be resized to approximately 140 x 60 pixels with a file size between 10 KB and 20 KB in JPEG format. That's a tiny file — and getting it right requires a clean scan of a clean signature. Use black ink on white paper, sign in your normal handwriting, and scan or photograph it in good lighting.
Railway forms also ask for a left thumb impression for some exams. Apply ink evenly to your left thumb, press firmly on white paper, scan it, and resize to the same dimensions as the signature. The impression should be clear with visible ridge patterns. If it's just a black blob, redo it with less ink.
The 15-40 KB Compression Challenge
This is the tightest file size range among major government exams, and it trips up a lot of people. Here's the workflow that works reliably. First, crop your photo to a 7:9 ratio (which matches the 35x45 mm requirement). Then resize it to 413 x 531 pixels. At this point your file is probably around 50-80 KB.
Compress Your Photo to Under 40 KB
RRB has the tightest file size limit among major exams. Use our JPG compressor to hit the 15-40 KB target without losing clarity.
Now compress the JPEG to your target. A JPG compressor can bring it into range. Target around 35 KB to give yourself some breathing room below the 40 KB cap. Always verify the final file size by right-clicking the file and checking properties (on Windows) or Get Info (on Mac).
iPhone Users: HEIC Won't Work
This catches thousands of candidates every cycle. iPhones save photos in HEIC format by default, and the RRB portal doesn't accept HEIC. You'll get a format error when you try to upload, and the portal won't tell you why — it'll just say "invalid file." The fix: convert your HEIC photo to JPG first, then resize and compress.
You can also change your iPhone settings to save photos as JPG going forward: go to Settings > Camera > Formats > Most Compatible. This saves everything as JPG from that point on, which makes all future exam form uploads simpler.
Portal Upload Problems — What Actually Helps
RRB portals are... temperamental. During peak registration periods, uploads fail randomly even when your files are perfect. Try these: use Chrome or Firefox (not Safari or Edge), clear your browser cache before starting, disable any ad blockers temporarily, and don't try uploading during the last 48 hours before the deadline when server load peaks.
If the upload keeps failing despite correct specs, try reducing the file size a bit more — sometimes the portal's file size check has a few KB of overhead. A photo at 38 KB might fail while the same photo at 35 KB goes through. It shouldn't work that way, but sometimes it does.
Quick Reference — RRB Photo Specs
Photo: 35 x 45 mm | ~413 x 531 px | 15-40 KB | JPG | White background | Recent photo. Signature: ~140 x 60 px | 10-20 KB | JPG | Black ink on white paper. Left Thumb: Same as signature specs | Clear ridge patterns | Left hand only. Processing order: Crop → Resize → Compress → Verify size → Upload. Keep your original studio photo for future exam cycles. Create exam-specific files each time rather than reusing old compressed versions.
RRB Group D vs NTPC vs ALP — Spec Differences
While the base photo specifications are the same across Group D, NTPC, ALP, and Technician exams, there are minor differences in what additional documents are required. Group D and NTPC typically ask for photo, signature, and left thumb impression. ALP (Assistant Loco Pilot) may also require a declaration certificate scan depending on the notification. Always read the specific exam notification carefully — don't rely on last year's requirements since they sometimes change.
Getting the Left Thumb Impression Right
The left thumb impression trips up more candidates than the photo itself. Use proper stamp pad ink (blue or black), not regular pen ink. Press your left thumb firmly onto the stamp pad, then press it onto clean white paper with steady, even pressure. Don't roll your thumb — just press straight down and lift. This gives a cleaner impression with visible ridge patterns.
Scan or photograph the impression in good, even lighting. Crop tightly around the impression, then resize and compress to meet the portal's requirements (usually 10–20 KB as JPG). If the ridges aren't clearly visible in the digital file, redo the impression — a smudged or unclear thumb print can be flagged during document verification.
Preparing Photos on a Budget
Not everyone has easy access to a photo studio, especially candidates in rural areas. A smartphone photo works perfectly well if you follow these steps: stand against a plain white wall (a white bedsheet on a wall works too), use natural daylight (face a window), hold the camera at face level, and take the photo from about 1.5 metres away.
After taking the photo, crop it to the correct aspect ratio (about 3.5 × 4.5 cm ratio), then resize to 413 × 531 pixels. Finally, compress the JPEG to land between 15 and 40 KB. The entire process takes under 3 minutes and costs nothing.
RRB vs SSC vs UPSC — Photo Size Comparison
If you're appearing for multiple government exams (which most aspirants do), here's a quick comparison. UPSC requires 4 × 5 cm photos (472 × 591 px, 20–300 KB). SSC uses 3.5 × 4.5 cm (413 × 531 px, 20–50 KB). RRB also uses 3.5 × 4.5 cm but with a tighter ceiling of 40 KB. And IBPS is completely different at 200 × 230 pixels with a 20–50 KB range.
The takeaway: you cannot use one photo file for all exams. Start with one high-quality studio photo and create exam-specific versions by cropping and resizing for each. Label your files clearly (e.g., "photo-rrb-413x531-35kb.jpg") so you never upload the wrong version.
Deadline Warning
RRB application portals experience the heaviest traffic in the last 48 hours before the deadline. Upload speeds slow to a crawl, and sessions frequently time out. Complete your photo upload at least 3-4 days before the final date. Keep multiple copies of your correctly-sized photo across devices so you can reattempt from anywhere.
Prepare All Your Exam Photos at Once
Resize and compress your photo for RRB, SSC, UPSC, and IBPS — all from a single master photo using our free tools.