Why Does My Compressed Image Look Blurry?
Over-compression causes two different types of visual degradation: blurriness (loss of fine detail and sharpness) and blocking (visible grid-like artefacts). Both come from setting the quality too low relative to the image content and dimensions. This guide explains the cause and gives you the exact settings to stay sharp.
Quick Answer
Over-compression causes two different types of visual degradation: blurriness (loss of fine detail and sharpness) and blocking (visible grid-like artefacts). Both come from setting the quality too low relative to the image content and dimensions.
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Step-by-Step Guide
5 steps · takes under 1 minute
Identify which problem you have
Blurry/soft: the image looks like it's out of focus — fine detail is smoothed away. This happens at quality settings below 60% for photos. Blocky/pixelated: you can see rectangular patches in the image. This is DCT blocking from very low quality settings (below 40%). Both are symptoms of too-aggressive compression.
Go back to the original if you have it
Once an image is compressed, that quality loss is permanent — you cannot un-compress it. Always work from the original uncompressed source. If you've overwritten the original, this is the most important lesson: always keep originals.
Recompress at 80–85% quality
If you're compressing photos for web use, 80–85% is the sweet spot — files are 60–80% smaller than lossless, but quality loss is invisible at normal viewing sizes and distances.
Match dimensions to display size
Blurriness is worse when a low-quality compressed image is also displayed larger than its pixel dimensions. A 400×300 image stretched to fill a 800×600 container looks doubly bad. Resize the image to match or exceed its display dimensions.
Use WebP for better quality at the same file size
WebP's compression algorithm is technically superior to JPG — at the same file size, WebP looks sharper. If JPG at 80% looks too soft, try WebP at 80% — the result is visually better at the same or smaller file size.
Before vs After Compression
Typical result on a 1080×1080px product photo
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Pro tip
Use 75–85% quality for web images — you get 60–80% smaller files with no visible difference at normal screen sizes.
Format & File Size Comparison
Same 1080×1080px photo processed four ways
| Format | Quality | File Size | Notes |
|---|---|---|---|
| PNG (original) | Perfect | 4.2 MB | No compression — too large for web |
| Compressed PNG | Visually identical | 1.1 MB | −74% — transparency preserved |
| JPG (85% quality) | Excellent | 310 KB | −93% · Best for photos |
| WebP (85%)BEST | Excellent | 205 KB | −95% · Recommended for web |
Based on a 1080×1080px photo. Results vary by image content and complexity.
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