We measured it: real file sizes
Settings: WebP, quality 80 (the defaults)
What the numbers sayAt the default WebP quality 80 the photo lost 46% (330.2 KB to 178.7 KB) and the illustration 70%. The biggest win is the screenshot at 85% — because it was a screenshot saved as JPG in the first place, the worst possible pairing. Note the savings depend far more on what kind of picture it is than on the quality slider.
Measured on 2026-07-28 by running these files through this very page in Chromium 151.0.7922.34. Every page uses the same published test files, so the numbers are comparable across converters.Method, and download the test images →
What is image compression?
Image compression means making the file as small as possible at an acceptable quality. This tool re-encodes your image to JPG or WebP locally in your browser, trading adjustable quality for a smaller file — great for speeding up websites, easy uploads and emails, and saving storage. Nothing is uploaded.
How to use it
- Drop in or select a JPG, PNG or WebP image.
- Pick an output format and drag the quality slider (lower = smaller file); optionally shrink the dimensions too.
- Compare the before/after size and click Download when happy.
Tips for a smaller file
- Use JPG or WebP for photos; images with large flat areas, lines or text sometimes stay crisper as PNG.
- If the image will be shown small (thumbnails, avatars), resizing it helps more than quality alone.
- A quality of 70–85 is usually the sweet spot between quality and size.
Several images on one page — which one do you compress first?
Percentages will send you to the wrong file. The prettiest ratio in our three rows belongs to the UI screenshot, 45.2 KB → 6.7 KB (-85%), and it recovers all of 38.5 KB. The photo’s -46% looks far less impressive yet frees 151.4 KB — 3.9× as much. The illustration sits in between at 25.6 KB → 7.7 KB (-70%), worth 18.0 KB. Load time is paid in bytes, not in ratios, so work down the list by absolute size and start with the biggest file. This run measured WebP at quality 80. One limit worth knowing first: choose JPG output and the code paints a white rectangle before drawing (#ffffff is hard-coded), so transparent areas come back white — not preserved, and not black either. Pick WebP when the alpha matters.
Frequently Asked Questions
How much can I expect to save, and what format comes out?
At the page defaults, which are WebP at quality 80, our three test files fell by 46%, 85% and 70% — the photo from 330.2 KB to 178.7 KB and a JPG screenshot from 45.3 KB to 6.7 KB. Note the output format: WebP by default, because that is what produced those numbers. Switch it to JPG if the destination cannot read WebP, and expect smaller savings.
Are my images uploaded?
No. Compression runs entirely in your browser using the Canvas API. Your images are never sent to a server or stored, so it is safe for private photos.
How much smaller can it get?
It depends on the original and the quality setting. Photos (JPG/WebP) typically shrink to 20–60% of their original size; a quality of 70–85 is usually visually indistinguishable while saving a lot of space.
Does compression reduce quality?
JPG and WebP are lossy, so a lower quality means a smaller file and more lost detail. Start around 80 and fine-tune while watching the output size to balance quality and file size.
Should I choose JPG or WebP?
WebP is usually smaller than JPG and supports transparency, making it ideal for websites. If you need compatibility with older software or platforms, JPG is the safest choice.
