Image Compressor
Shrink a JPEG or WebP file size with an adjustable quality slider, or hit an exact KB target.
About this tool
This tool re-encodes a JPEG or WebP image at a lower quality setting to reduce file size, using your browser's built-in Canvas API — the same underlying compression a desktop image editor would use, just running locally instead of needing software installed.
Two modes are available. Manual Quality gives you direct control over the quality percentage, showing the resulting size live as you drag the slider. Target File Size does the opposite: tell it a KB limit (useful for exam or government form uploads that specify an exact maximum, like "under 100 KB") and it automatically searches for the highest quality that still fits under that limit, rather than you guessing and re-checking repeatedly.
If even the lowest quality setting can't get under your target size, that means quality reduction alone isn't enough — the image's pixel dimensions are also contributing to the file size. Resize it smaller first with the Image Resizer, then compress again.
PNG images are not re-compressed with a quality slider the same way — PNG is lossless, so "quality" doesn't apply the same way it does to JPEG. If you upload a PNG, converting it to JPEG first (see the Format Converter) usually gives a much smaller file when photographic detail is present.
Frequently asked questions
Does this work on PNG files?
You can upload one, but PNG compression is lossless and doesn’t have a quality slider the same way JPEG does. For a photographic PNG, converting to JPEG first (Format Converter) usually shrinks the file far more.
Is the image uploaded anywhere?
No — compression happens entirely in your browser using the Canvas API. The file never leaves your device.
What quality setting should I use?
70-85% is a common sweet spot for web images — noticeably smaller than the original with minimal visible quality loss. Go lower for thumbnails, higher for images where fine detail matters.
How does Target File Size find the right quality?
It tries a range of quality values and keeps the highest one that still produces a file at or under your target size, so you get the best possible quality that fits your limit without manual trial and error.
What if it can’t hit my target size at all?
The tool tells you rather than silently giving up — that means the image’s pixel dimensions are too large for quality reduction alone to reach your target. Resize it smaller with the Image Resizer first, then compress again.