Question 1

Does compressing an image reduce visual quality?

Accepted Answer

It depends on the compression level and format. Lossy formats like JPEG and WebP discard color information imperceptible to the human eye. At 75–90% quality, the difference is rarely visible — but aggressive compression below 60% introduces visible artifacts, especially on edges and gradient areas.

Question 2

What is the difference between lossy and lossless compression?

Accepted Answer

Lossy permanently discards data to reduce file size — JPEG and WebP work this way. Lossless keeps all original data — PNG and ZIP compression work this way. Lossless image compression generally produces larger files than lossy for the same content.

Question 3

Does PNG compress more than JPEG?

Accepted Answer

For natural photographs, no. JPEG was designed for photos and achieves much greater reductions at acceptable quality. PNG excels for illustrations, text screenshots, icons and any image where transparency or exact sharpness matters. Comparing PNG and JPEG without considering content type leads to wrong conclusions.

Question 4

Is WebP always better than JPEG?

Accepted Answer

In practice, WebP produces files 25–35% smaller than JPEG at equivalent visual quality. The real limitation is compatibility: legacy systems, email and third-party tools may still reject WebP. For modern web, WebP is the superior technical choice. For universal sharing, JPEG remains safer.

Question 5

Is the image sent to the server during compression?

Accepted Answer

No. All processing happens locally in your browser using the Canvas API. No pixel is transmitted to any server — not the content, not the filename, not the metadata.

Question 6

How does max width affect compression?

Accepted Answer

Large images have more pixels to store, so they are bigger. Limiting max width resizes the image before compressing, resulting in a smaller final file. For social media, most platforms resize automatically during upload — sending a smaller image saves bandwidth and upload time.

Question 7

What is EXIF metadata and why does it increase file size?

Accepted Answer

EXIF is data embedded in the image by the camera or app: date, GPS coordinates, device model, exposure settings, thumbnail and more. It can take up tens of kilobytes. Canvas re-encoding removes these automatically, contributing to size reduction — and to privacy.

Question 8

Why do some images not get much smaller even with low quality?

Accepted Answer

Already-compressed images have little room for further reduction. Photographs with heavy noise or digital grain are especially resistant — the lossy algorithm handles randomness poorly. Vector illustrations converted to raster and low-detail photos usually compress well. If the reduction was small, the file was already near the theoretical limit for that content.

Image Compressor

Image compression: what really happens when you reduce a photo's file size

Three steps to compress images without surprises

Sources and references for this tool

Frequently asked questions

Image compression: what really happens when you reduce a photo's file size

Three steps to compress images without surprises

Sources and references for this tool

Frequently asked questions

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