Online forms for jobs, exams, university admissions and government services often ask for a photo “less than 100 KB” and a signature “less than 50 KB” or even 20 KB. A photo straight from your phone is usually 2–5 MB, which is 20 to 50 times too big. Here’s how to get it to the right size quickly, for free, and without uploading your photo to a stranger’s website.
File size vs. picture size
Two different things decide how “big” a photo is:
- Dimensions (pixels): how wide and tall the picture is, for example 4000 × 3000 pixels.
- File size (KB or MB): how much space the file takes. It depends on the dimensions and on the quality (compression) setting.
To reach a small file size you usually lower both: make the picture narrower and save it at a slightly lower quality. A passport-style photo only needs a few hundred pixels across to look sharp in an application, so you lose nothing that matters.
How to compress a photo to under 100 KB
- Open the free Image Compressor.
- Set Output format to JPG. Almost every form accepts JPG. Many don’t accept WebP, even though it’s smaller.
- Type a Max width, for example 1000, and set Quality to about 70%.
- Choose your photo. You’ll see the old and new size, for example “3.2 MB → 85 KB”.
- If it’s still over the limit, lower the max width (try 800) or the quality (try 60%), then choose the photo again. When it fits, click Download.
Good starting settings for each size limit
These are first tries for a normal phone photo. Then adjust as described above.
| Size limit | Max width | Quality |
|---|---|---|
| Under 200 KB | 1600 px | 75% |
| Under 100 KB | 1000 px | 70% |
| Under 50 KB | 700 px | 65% |
| Under 20 KB | 400 px | 60% |
Photos with lots of detail, like trees, crowds or patterned clothes, need lower settings. Photos with a plain background, like a passport photo against a white wall, get much smaller.
When the form asks for exact dimensions
Some forms want a specific shape or pixel size, for example a 3:4 portrait or exactly 300 × 400 pixels. Do it in this order:
- Crop the photo to the right shape with Crop Image. Pick the 3:4 or Square 1:1 shape so your face is in the middle.
- Resize it to the exact pixels with Resize Image. Choose “Exact size (pixels)”.
- Compress it with the Image Compressor, leaving “Max width” empty so the size stays the same.
Making a signature image under 20 KB
Sign on plain white paper with a dark blue or black pen. Take the photo in daylight, holding the phone straight above the paper so there are no shadows. Crop tightly around the signature, then compress it with a max width of about 400 px. Because a signature is mostly white space, it usually ends up well under 20 KB.
Common questions
Why is my photo still large after compressing?
Check that the output format is JPG, not PNG. PNG keeps every pixel exactly and is much bigger for photos. Then lower the max width.
Will the photo look blurry?
Not at the sizes in the table above. Forms show your photo small, so 400–1000 pixels across looks sharp. Only very low quality settings (below about 50%) start to look blocky.
Can I do this on my phone?
Yes. All the tools work in your phone's browser. Choose the photo from your gallery and the result is saved to your downloads.
Is my photo uploaded anywhere?
No. ToolNest compresses the photo inside your own browser, so it never leaves your device.