How-to Guide 3 min read

How to Fix Pixelated or Blurry Compressed Photos

Pixelation and blocking in compressed photos comes from over-compression — the quality was set too low for the image dimensions and content. Once a photo is compressed and saved, those artefacts are baked in. This guide explains how to prevent it in future, and what options exist to partially recover quality from an already-degraded image.

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By ImgToolkit Team · Updated May 2026 · 3 min read · Processed in your browser
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Quick Answer

Pixelation and blocking in compressed photos comes from over-compression — the quality was set too low for the image dimensions and content. Once a photo is compressed and saved, those artefacts are baked in.

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Step-by-Step Guide

5 steps · takes under 1 minute

1

Prevention: use 80% quality minimum

Pixelation appears when JPG quality drops below 60–65% for photos. At 80%, compression is aggressive but artefacts are invisible. At 70%, they become visible on close inspection. At 60% and below, blocking becomes obvious even at normal viewing distances.

2

Work from the original, not from a compressed copy

If you have the original uncompressed file (RAW, TIFF, or 95%+ JPG), recompress from it at a higher quality. Once compressed, that quality loss is mathematically irreversible — but the original still contains the full detail.

3

Use AI upscaling to partially recover lost detail

Tools like Topaz Gigapixel AI, Let's Enhance, Waifu2x (free, for anime/illustrated content), or Adobe Lightroom's AI denoise can use machine learning to synthesise plausible detail. Results vary — they work best on moderate compression and less well on severe pixelation.

4

Use our Upscale tool to increase resolution

The ImgToolkit Upscale tool uses bicubic interpolation to increase resolution by 2× or 4×. This doesn't add real detail, but it smooths out blocky pixelation through resampling, which can make severely compressed images look less obviously degraded.

5

Convert to WebP for future compression

WebP's compression algorithm produces fewer artefacts than JPG at equivalent quality settings. For future compressions, switch to WebP — the same visual quality threshold requires 25–35% less file size, or conversely, the same file size gives you noticeably better quality.

Before vs After Compression

Typical result on a 1080×1080px product photo

Before 4.2 MB
📷 Original PNG
After 820 KB
🗜️ −80% smaller
Before: 4.2 MB — slow to load, rejected by email
After: 820 KB — fast loading, visually identical
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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

FormatQualityFile SizeNotes
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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Frequently Asked Questions

4 questions answered

What causes the blocky grid pattern in compressed photos?

JPG compression works by dividing the image into 8×8 pixel blocks and compressing each block using Discrete Cosine Transform (DCT). At high quality settings, differences between adjacent blocks are subtle and invisible. At low quality, the blocks become visible as a grid pattern — called DCT blocking or mosquito noise. It's most visible in smooth gradients (sky, skin tones).

Can I remove JPEG compression artefacts without the original?

Partially. AI denoising tools (Topaz DeNoise AI, DxO PhotoLab's DeepPRIME, Lightroom's AI denoise) can substantially reduce compression artefacts. Free options include Waifu2x (excellent for anime/illustration) and Let's Enhance (photo-focused). Results depend on severity — mild compression responds much better than severe pixelation.

Why does my photo look pixelated when I zoom in but fine at normal size?

Every digital image appears pixelated when zoomed in enough — that's the nature of raster graphics. The question is whether it looks pixelated at the intended display size. If it's fine at 100% view (actual display size) but looks bad zoomed in, your compression is actually fine — don't compress less. Only fix it if artefacts are visible at the actual display size.

Is there a difference between pixelation and compression artefacts?

Yes. Pixelation is when you can see individual square pixels — caused by displaying a low-resolution image at a larger size (upscaling). Compression artefacts are patterns caused by lossy encoding — ringing around edges, blocking in flat areas, mosquito noise in gradients. Both look bad but have different causes and different fixes.

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