Compress Image to 20KB — Free, Fast & Private
20KB is one of the strictest file size limits you will encounter — common for signature uploads and small profile photos on Indian government exam portals. SSC, IBPS and SBI require signature images of 10–20 KB, and the bank exams want passport photos of 20–50 KB. Two big portals go the other way: RRB's signature must be 30–49 KB and UPSC's 20–300 KB, so both portals refuse a file under 20KB at upload.
What fits in 20 KB — measured on this page
We dropped five real files on the compressor above and kept what it handed back. 5 of 5 came out under 20 KB; 3 were made smaller in pixels to get there, because past a point the bytes can only come from pixels.
| File | Before | After, on this page | Under 20 KB? |
|---|---|---|---|
| 12 MP phone photo | 4032 × 3024 px · 3.73 MB | 1278 × 959 px · 13.9 KB | Yes |
| Portrait / headshot | 3264 × 4653 px · 2.25 MB | 1632 × 2327 px · 19.2 KB | Yes |
| Scanned handwritten page | 3349 × 4281 px · 2.17 MB | 1368 × 1749 px · 16.7 KB | Yes |
| Scanned signature | 2041 × 617 px · 109.1 KB | 2041 × 617 px · 19.5 KB | Yes |
| Screenshot (PNG) | 1280 × 800 px · 88.1 KB | 1280 × 800 px · 19.4 KB | Yes |
Measured 2026-10-07 in Chromium 145.0.7632.6 with this page’s own settings. The photos are public-domain and CC0 files from Wikimedia Commons; the screenshot is our own. Sizes read as the tool shows them (1 KB = 1,024 bytes); the target itself is 20,000 bytes, which is under 20 KB on either reading.
To hit 20KB, you need aggressive compression combined with dimension reduction. MiniPx makes this straightforward: this page is already set to a 20KB target, so the engine walks quality down and, when quality alone cannot get there, steps the dimensions down for you and tells you the size it landed on. Pick JPEG, and drop the Max width pill to 640px if you want the smaller starting point. Signatures land under 15KB, passport-style photos at 15-25KB. When 15 KB is the number on your form, compress to 15 KB instead.
The key to reaching very small file sizes is reducing pixel dimensions. A 4000px wide phone photo compressed to 20KB would be extremely blurry. But the same photo resized to 400-640px width and then compressed looks perfectly clear at the small display sizes used by government portals. MiniPx handles both the resizing and compression in a single step. If your portal allows a photograph a little more room, a 25 KB target keeps more detail.
MiniPx shows the exact compressed file size next to your image, so you can verify it meets the 20KB requirement before downloading. If you are still slightly over, reduce the max width further. MiniPx processes everything in your browser — your exam photos, signature scans, and identity documents never leave your device.
Common portals requiring a signature of at most 20KB include: SSC CGL/CHSL/GD/MTS, IBPS PO/Clerk, SBI PO/Clerk, and various state PSC exams. MiniPx works with all of them (the SSC signature tool aims inside SSC's band). Not UPSC or RRB: their signature floors sit at or above 20KB.
If the form gives a minimum as well as a maximum, see between 10KB and 20KB and between 20KB and 50KB.