FILE WORKFLOW GUIDE
How to compress an image to 100 KB
Set a 100 KB target, check the downloaded file, and reduce pixel dimensions if quality alone cannot meet the limit. A target size is best effort, not a guarantee.
Start with the upload requirement
| Requirement | What to change |
|---|---|
| Under 100 KB | Compression quality, format, then dimensions if needed |
| No wider than 1200 px | Maximum width in the image resizer |
| JPEG only | Output format and background color |
A file-size limit and a pixel-size limit are different. An image can be 800 pixels wide and still exceed 100 KB. Check whether the receiving site asks for JPEG, requires a specific width, or rejects transparent images before choosing settings.
Compress and check in four steps
- Open the image compressor and add a JPG, PNG or static WebP image up to 10 MB.
- Choose JPEG for a form that requires JPG, or WebP if the receiving site accepts it. JPEG fills transparent areas with the selected background color.
- Enter 100 in the target-size field. Process and download the image, then open it to inspect small text, edges and faces.
- Check the downloaded file against the destination's limit. FileUnbox treats each KB as 1,024 bytes; for a strict 100,000-byte cap, use 97 KB or lower and verify the result.
If the target cannot be reached
The compressor searches for a quality level that fits the target without changing pixel dimensions. Some detailed or large images remain too big even at low quality. A warning means the downloaded file may exceed your target; it is not a successful 100 KB conversion.
Resize the original to the maximum dimensions you actually need, download the PNG result, then compress that PNG to JPEG or WebP. Do not repeatedly re-encode the same JPEG if you still have the original. If a form requires both very high resolution and a tiny file, you may need to clarify its requirements.
A dimension example, not a compression promise
| Input | Maximum dimensions | Resize output |
|---|---|---|
| 2400 × 1600 px | 1200 × 1200 px | 1200 × 800 px PNG |
| 600 × 400 px | 1200 × 1200 px | 600 × 400 px PNG; no upscaling |
These dimensions illustrate proportional resizing. Final bytes depend on the actual picture, output format and browser encoder; resizing alone does not guarantee 100 KB.
What happens to your image?
Compression, conversion and resizing run locally in the browser. They do not require an account or AI access code, and the file content is not sent to a server. Keep the original until you have checked the new copy.