Question 1

Is this image compressor really free and private?

Accepted Answer

Yes — completely free and completely private. The entire compression pipeline runs in your browser using the HTML5 Canvas API. Your images are read as local files, processed with JavaScript, and compressed to Blob objects in memory. Nothing is uploaded to any server, so there is no file size limit, no queue, and no risk of your images ending up in someone else's storage. You can verify this yourself: disconnect your network after loading the page and compression still works.

Question 2

Which image formats can I compress, and what quality should I use?

Accepted Answer

This tool accepts JPG/JPEG, PNG, and WebP images. For JPG and WebP sources, quality levels between 70-85% are the sweet spot: visually indistinguishable from the original for most photos while cutting file size by 50-80%. PNG images use lossless compression, so they rarely shrink — for PNG files we recommend switching the output format to WebP, which can reduce photo-style and illustration PNGs by 60-90% while staying visually identical. A quality of 75% is the conventional default used by most compression services.

Question 3

How much can I compress an image without visible quality loss?

Accepted Answer

Typical results for photographic images: a 5 MB JPG from a modern smartphone compresses to 600-900 KB at quality 75% (roughly 80-88% smaller) with no visible difference at normal viewing sizes. Screenshots with lots of flat color and text compress even better — often 90%+ smaller when converted to WebP. The exact ratio depends on image content: noisy photos (high ISO, film grain, night shots) compress less because the noise is high-frequency detail that compression must preserve to stay clean. That is why this tool shows a live before/after size comparison — you can drag the quality slider and watch the byte count change until the visual trade-off feels right for your use case.

Question 4

Is the compressed image quality the same as TinyPNG or other online compressors?

Accepted Answer

For JPG and WebP, browser-native encoding (what this tool uses) produces results comparable to most online services — typically within a few percent of file size at the same quality setting. The main difference is transparency: TinyPNG's advanced PNG quantization can shrink PNGs more aggressively than the browser's native PNG encoder, which is lossless and won't reduce PNG size much. The workaround is simple: convert PNGs to WebP instead, which gives transparency support plus compression that beats TinyPNG's PNG output in most cases. This tool runs locally, has no upload queue, and imposes no file count or size restrictions — unlike free tiers of online services.

No upload	Images are processed as local `File` objects via the Canvas API and never sent over the network. You can compress sensitive screenshots, design assets under NDA, or client photos without a second thought.
No limits	Because nothing reaches a server, there is no file-size cap and no image-count quota. Compress 200 screenshots in one batch if you need to.
Honest comparison	Every card shows original size, compressed size, and the exact percentage saved — recomputed live as you move the quality slider. You never compress blind.
Transparency	JPG and WebP use lossy compression at your chosen quality; PNG stays lossless (which is why PNGs shrink only when you switch output to WebP). The recommended path for screenshots and illustrations is WebP output.
Batch workflow	Drop a folder of assets, set quality once, download the whole batch as individually named files with a single click.

Image Compressor

How the compression works — and why it beats uploading to a service

What quality setting should you use?

Frequently asked questions