Question 1

Are my photos ever uploaded to a server?

Accepted Answer

Never. Image Compressor by Qanen runs 100% on your device. JPEG and WebP are re-encoded by your browser's built-in canvas encoder, while AVIF and lossless PNG use WebAssembly codecs (libavif and UPNG) loaded locally — no files are ever uploaded. Once the codecs are cached, you can even disconnect your network and the tool keeps working.

Question 2

Which format should I choose?

Accepted Answer

WebP is recommended for 95% of use-cases due to universal browser support and outstanding compression ratios. AVIF offers even smaller file footprints for modern browsers, while JPEG provides legacy fallback.

Question 3

Is there any file limit or paywall?

Accepted Answer

No limits, no subscriptions, and no quotas. Because your device's own CPU and memory handle the calculations, you can compress as many gigabytes of images as your computer hardware supports.

Question 4

Does Image Compressor work offline?

Accepted Answer

Yes. After the page and its WebAssembly codecs have loaded once, compression runs entirely on your device, so you can keep working without an internet connection. Nothing is sent anywhere either way.

Question 5

How do I compress images without losing quality?

Accepted Answer

Use the Lossless preset for pixel-perfect PNG output, or a high-quality WebP (the Balanced preset defaults to quality 82) which is visually indistinguishable from the original at a much smaller size. The built-in comparison slider lets you confirm the quality before you download.