How compressing to an exact size works
Most image compressors give you a quality slider and leave you to guess. If a form says “maximum 200 KB”, you drag the slider, save, check the size, drag again, and repeat until it fits. This tool works backwards from the limit instead. You state the size you need and it searches for the highest quality that still fits under it, so you keep as much of the picture as the limit allows.
If even the lowest useful quality is still too big, the image is scaled down a step and the search runs again. If a target is genuinely out of reach, you are given the smallest result the tool could produce, clearly labelled, rather than a silent failure.
A simple way to choose a target
| Where the image is going | A sensible target |
|---|---|
| Government and exam portals (signatures, small photos) | 20–50 KB, or whatever the notice says |
| Job applications and admission forms | 100 KB |
| Marketplace and product photos | 200 KB |
| Website hero images | 300–500 KB |
| Email, claims, tickets | 1 MB |
The pages for each size explain what fits and who asks for it: 20 KB, 50 KB, 100 KB, 200 KB, 500 KB and 1 MB.
What compression does to a picture
JPEG and WebP are lossy formats. They discard fine detail that the eye is poor at noticing, keeping edges and overall brightness, which is why a well-compressed photo looks nearly identical at a fraction of the size. Two levers decide the size: quality (how much detail is discarded) and dimensions (how many pixels there are). Dimensions usually matter more: halving both width and height removes 75% of the pixels. That is why the tool lowers the quality first, and reduces the dimensions only when quality alone cannot reach the limit.
Good habits
- Compress from the original, not from a copy that was already compressed. Each lossy save loses more.
- Crop first if you do not need the whole frame. Fewer pixels leave a larger budget per pixel.
- Use JPG for photos. A photograph saved as PNG is several times larger with no visible benefit. Convert it first.
- Look at the result at 100%. Faces, text and thin lines show damage first.
- Set other requirements together. If you also need exact dimensions or a different format, switch those on and everything is applied in one pass.
Privacy
Compression happens in your browser. Your images are read on your device, processed there and offered for download without being uploaded, which makes the tool safe for IDs, signatures and personal photos. Re-encoding also drops camera and location metadata. For a deeper explanation of what makes images big, see the guide on reducing image size without losing quality.