To compress an image to a specific size such as 100 KB, use a tool that aims for a file size rather than a quality setting. In the JFDI image editor, open the picture, choose Aim for a size under Save as, type 100 KB, and download. The editor tries quality levels until it finds the best one that fits under 100 KB. If even the lowest sensible quality is too big, it makes the picture smaller in pixels until it fits, and tells you.
Why forms ask for 100 KB
Job applications, exam registrations, government portals and membership systems often set a maximum file size for photos and signatures, commonly somewhere between 20 KB and 500 KB. A photo straight from a phone is usually 2 to 5 MB, so it needs to be 20 to 50 times smaller.
You can get there by trial and error with a quality slider, or let the tool do the search.
Step by step
- Open the image editor and drop in your picture (or several; each one is handled separately).
- Crop it first if the form wants a particular shape, such as a square or passport proportions. Click the crop button above the picture, or pick a shape under Crop.
- Resize it if the form gives pixel dimensions, under Resize. A smaller picture needs less compression to hit a size, so it looks better. For a 100 KB limit, around 800 to 1,200 pixels on the longest side is usually plenty.
- Under Save as, choose JPG and switch to Aim for a size. Type 100 KB (or whatever the form says).
- Check the preview. The list on the left shows the new file size. Zoom to 100% to check faces and text are still clear.
- Download.
The editor saves each file as close to the target as it can without going over, so it won’t fail a strict upload check.
KB or KiB?
Some forms count 1 KB as 1,000 bytes and others as 1,024. If a form rejects a file that should fit, aim a few kilobytes lower, such as 95 KB for a 100 KB limit.
Which format?
| Format | Use it when |
|---|---|
| JPG | Photos and scans for forms. Accepted everywhere. |
| PNG | Signatures, logos and screenshots with sharp edges and few colours. |
| WebP | Websites. Smaller than JPG at the same quality, but some forms won’t accept it. |
For a PNG, quality can’t be lowered because PNG is lossless. The editor reduces the number of colours instead (256 colours usually looks identical for screenshots and logos), then the pixel size, until the file fits.
Getting the best quality at a small size
- Crop away background. Fewer pixels of wall means more detail for the face.
- Resize before compressing. A 1,000-pixel photo at good quality looks better than a 4,000-pixel photo squeezed hard.
- Avoid noise. Photos taken in dim light have grain, which compresses badly. Take the photo in good light.
- Check text at 100% zoom. For scanned documents, make sure small print is still readable.
What happens to the photo’s hidden details
Phone photos contain the location where they were taken, the date and the camera model. The editor removes these by default, which also saves a few kilobytes. See how to remove location data from photos.
Is it private?
Yes. The photo is compressed in your browser and never uploaded. That matters for ID photos and signatures, which are exactly the images you shouldn’t scatter across free websites.