Image Optimizer — WebP, AVIF & MozJPEG Local
Optimize images for the web in your browser with MozJPEG, WebP, AVIF, or OxiPNG. Steps: choose a photo, load the optimizer engine, pick a codec and settings, compare before/after with the slider, then download. Example: turn a large hero JPEG into a smaller WebP for faster pages — files stay on your device after you load the engine.
How it works
Choose a photo, load the optimizer engine once, pick MozJPEG, WebP, AVIF, or OxiPNG, tune quality or effort, optionally cap the longest side, then slide to compare before and after. Encoding runs in this tab; download when the size and look feel right. Prefer the quick compressor when you only need a fast size cut without codec controls.
Rules you should expect
Codecs trade size, quality, transparency, and time differently. Use this checklist before you chase the smallest file.
- MozJPEG: lossy JPEG with stronger compression than a typical browser JPEG export — good when you still need .jpg compatibility.
- WebP: usually smaller photos than JPEG at similar look; supports transparency. Solid default for many sites.
- AVIF: often the smallest lossy files, but encoding is slower — progress and cancel are expected, not optional.
- OxiPNG: lossless PNG shrink. Photos stay large; best for sharp UI with alpha. Re-encode usually drops EXIF; bytes never leave this tab.
Example
Same ~3–4 MB phone JPEG: MozJPEG often lands smaller than a casual browser JPEG; WebP commonly trims further at a similar look; AVIF may shrink more again but can take seconds on a large frame. Numbers vary by content — treat them as order-of-magnitude, then trust the slider on your file.
Good fits
- Ship a hero or product shot as WebP/AVIF after checking look with the compare slider.
- Keep JPEG delivery but use MozJPEG when browser-default JPEG still feels too heavy.
- Shrink transparent UI PNGs with OxiPNG or near-lossless WebP before handing assets off.
Frequently asked questions
How is this different from the image compressor?
The compressor is a fast canvas resize/quality pass (great for target KB). This page loads a dedicated engine so you can choose MozJPEG, WebP, AVIF, or OxiPNG and compare with a slider.
Do my files leave the browser?
No. After the engine loads, decode and encode stay in this tab. Confirm in DevTools Network that the image is not POSTed.
Why do I have to load an engine first?
The codecs are large. We wait for a click so the first paint stays light — you download them only when you need codec-level optimize.
Why is AVIF so slow?
AVIF encoding is CPU-heavy, especially on big photos. We show progress and let you cancel instead of pretending it is instant.
What about animation and EXIF?
Animated inputs become a still of the first frame. Re-encoding usually strips EXIF — inspect tags with the EXIF tool first if you need them.
When should I use the format converter instead?
Use the converter when you mainly need to change MIME (including JPEG matte for transparency). Use this optimizer when smaller files and codec control matter more than a quick format swap.
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Questions or feedback
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