Compress an Image to 20KB
20KB is about the smallest upload limit you'll run into, usually on the signature and photo fields of exam, job and scholarship applications. FormShrink compresses your image to 20KB or less as a JPG. Large photos are scaled down to 800 px on the longest side first, because a full-size photo can't get anywhere near 20KB.
It all happens in your browser. Your photo or signature is never uploaded, and there's nothing to sign up for.
This page presets the tool: Advanced mode, JPG output, a 20KB target and resizing to fit within 800 × 800 px. Change any of it under Compression Settings; Reset Settings brings the preset back.
Drop your images here
Click to select images
The target size comes first: FormShrink lowers the quality below your chosen level when needed to reach it.
Higher values preserve more detail but produce larger files.
Lanczos3: higher quality (slower), Bilinear: faster (lower quality).
Leave blank to let FormShrink decide the optimal size.
EXIF data such as camera details and GPS location is removed automatically
JPEG · PNG · WebP support target size compression. Other formats need to be converted first.
How to compress an image to 20KB
Crop, then add the image
Crop tightly to the face or the signature in your phone's photo editor or any image editor, then drag the file here or click Browse Files. JPG, PNG, WebP, GIF, BMP and TIFF are accepted.
Match the form
The 20KB target and 800 px limit are already set. If the form asks for exact pixel dimensions, enter them under Resize Image and switch off Maintain aspect ratio. If it doesn't, a smaller Width and Height such as 500 px gives a cleaner result.
Compress and check
Click Compress Images and FormShrink compresses the image to 20KB or less at the best quality that fits. The results show the new size and pixel dimensions. If 20KB can't be reached, lower Width and Height and try again.
Where 20KB limits show up
Limits this small usually come from systems that store files for huge numbers of applicants, or from forms built years ago that nobody has updated since.
Signature uploads
Signature fields on application forms are often capped at 10–20KB. Sign with a dark pen on plain white paper, photograph it in even daylight and crop close around the ink. A signature has so little detail that it fits in 20KB with room to spare, even at 600 px wide.
Strict photo fields
Some exam and recruitment portals allow only 20KB for the applicant photo. A head-and-shoulders crop at 400–600 px on the longest side keeps the face clear at this size, while the same photo at 800 px looks noticeably blockier.
Thumbnails and previews
Catalogs, spreadsheets and internal tools that store a small preview for every record often want tiny files. A 20KB JPG at 300–400 px is plenty for a thumbnail.
Getting a clear result at 20KB
- Fewer pixels means more quality per pixel. A portrait photo 500 px tall usually looks cleaner at 20KB than the same photo at 800 px, so lower Width and Height if the form doesn't require a particular size.
- Plain backgrounds compress far better than busy ones. If you're taking the photo yourself, stand in front of a plain, light-colored wall.
- 20KB here means 20,480 bytes (1KB = 1,024 bytes). If the form counts 1KB as 1,000 bytes, a 20,000-byte limit needs a target of 19KB.
- JPG can't store transparency, so a signature saved as a transparent PNG may end up on a black background. Use a signature photographed on white paper, or choose PNG as the Output Format if the form accepts PNG.
Questions about compressing to 20KB
Can any photo be compressed to 20KB?
Most can, once they're small enough in pixels. At 800 px on the longest side a typical photo fits in 20KB, but only at low quality, and very detailed scenes may not fit at all. Around 500 px looks much cleaner. If 20KB can't be reached, the tool tells you instead of handing you a file that's too big.
The form needs 10–20KB, but my file came out smaller. What now?
With a target set, FormShrink looks for the highest quality that fits, up to the Visual quality setting (Balanced, or 80, by default). Simple images such as signatures can land well under 20KB. Set Visual quality to High (best detail) or raise the Fine-tune slider. If the file is still too small, the image has too few pixels: scan or photograph it at a higher resolution and increase Width and Height.
What pixel size should a 20KB photo be?
If the form gives dimensions, use exactly those. Otherwise, 400–600 px on the longest side suits ID-style photos, and 300 × 300 px is a common size for small profile pictures. Enter the size under Resize Image; with Maintain aspect ratio on, the image is fitted inside that box without being stretched.
I added a PNG. Why do I get a JPG?
This page outputs JPG because it reaches tiny sizes with the least visible damage, and it's the format most forms ask for. The download keeps its file name with a .jpg extension. If you need a PNG, change Output Format. To reach 20KB the tool then reduces the number of colors and, if needed, shrinks the image.
Is my signature uploaded anywhere?
No. The compression engine runs inside your browser, so your signature and photos never leave your device. Once your first image has been processed, the tool even keeps working with your internet connection turned off.
Other sizes and formats
- Compress image to 50KBGet a photo or scan under 50KB for an online form: JPG output, automatic resizing, nothing uploaded.
- Compress image to 100KBMeet a 100KB limit for forms, ID scans or web pages: JPG output at up to 1280 px, compressed locally in your browser.
- Compress JPGShrink JPG and JPEG photos by re-saving them at a quality you choose, 10 at a time, without uploading them.
- Reduce image file sizeShrink photos with the tools built into Windows, Mac, iPhone and Android, keep the original dimensions when you must, and get under email limits.
- Compress Images Online – JPG, PNG & WebP