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title: "Does Compressing an Image Reduce Quality? Six Myths Checked"
description: "--- English / EN. Does compressing an image reduce quality? Sometimes it does and sometimes it does not, and the difference comes down to which kind ran."
tags: ["compressing", "image", "reduce", "quality"]
canonical_url: https://image-compressor-saas.shop/blog/does-compressing-image-reduce-quality
English / EN. Does compressing an image reduce quality? Sometimes it does and sometimes it does not, and the difference comes down to which kind ran. Lossy compression discards high frequency detail for good.
Lossy and lossless discard different things. - Lossy compression drops detail the eye struggles to notice, including the colour information that chroma subsampling halves or quarters
- Lossless compression changes nothing but the encoding, so PNG, ZIP and lossless WebP restore every pixel exactly
- The quality slider on a JPEG export controls how aggressive the quantisation table is, and even 100 stays lossy
- Lossy WebP and AVIF discard data too, they just hide the damage better at the same file size
- HEIC borrows video compression machinery and pays for its small files the same way
One question settles it: can the pixels be restored exactly? If yes, the route was lossless. If no, data left the building.
What one pass actually costs. Take a JPEG straight out of a camera down to 60 or 75 percent quality, zoom to actual pixels and inspect a flat area. Faint banding shows up in a sky or a painted wall.
Six claims, checked one at a time. - Every kind of compression costs quality. Wrong.
The part worth keeping: Compress once on image-compressor-saas.shop and keep the master file separate, with nothing leaving your machine. Full write-up is on the source blog.
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