A complete reference for compressing images. Reduce file sizes while maintaining visual quality with our free Image Compressor tool.
Image compression reduces the file size of an image by removing or approximating visual data. The goal is to minimize file size while preserving acceptable visual quality. Compression is essential for web performance — a compressed image can load 5–10x faster than its uncompressed equivalent. There are two main types: lossy compression permanently removes data (smaller files, potential quality loss) and lossless compression reduces file size without altering any pixel data.
Lossy compression achieves the smallest file sizes by discarding visual information that the human eye is less sensitive to. The quality level (typically 0–100) controls how much data is removed. At high quality settings (80–90%), the difference from the original is usually imperceptible.
Best for: photographs, hero images, complex graphics where small file size matters. Formats: JPEG (lossy), WebP (lossy), AVIF (lossy).
Lossless compression reduces file size without altering any pixel data. The decompressed image is bit-for-bit identical to the original. Compression ratios are more modest (typically 20–50% reduction) compared to lossy methods.
Best for: screenshots, images with text, diagrams, and any image where perfect reproduction is required. Formats: PNG, WebP (lossless), GIF, SVG.
| Quality | Visual Quality | Size vs Original | Use Case |
|---|---|---|---|
| 90–100% | Identical to original | 10–30% smaller | Archival, print-quality, photography portfolios |
| 70–85% | Visually lossless | 40–70% smaller | Default for most web images |
| 50–70% | Slight degradation | 60–85% smaller | Thumbnails, background images, decorative |
| <50% | Noticeable artifacts | 85–95% smaller | Placeholder, low-bandwidth, previews |
80% quality is the sweet spot for most web images. It provides visually lossless results with substantial size savings. If the file is still too large, drop to 70% and compare visually. If quality is lacking, raise to 90%.
Photos with smooth gradients (skies, skin tones) show compression artifacts more readily than images with lots of detail or texture. Screenshots with text and sharp edges benefit from lossless formats like PNG or WebP lossless.
Each format handles compression differently. WebP at 80% quality often looks better than JPEG at 80% quality at the same file size. AVIF achieves even better ratios. Use the Image Converter to experiment across formats.
Compression alone cannot fix oversized images. A 4000px-wide image compressed to 80% will still be much larger than an 800px-wide image at 90%. Always resize images to match their display size before compressing.
| Image Type | Recommended Format | Quality | Notes |
|---|---|---|---|
| Photographs | WebP or JPEG | 80–85% | WebP gives 25–35% better compression than JPEG |
| Screenshots | PNG or WebP (lossless) | 100% | Lossless preserves text and UI element sharpness |
| Logos & Icons | SVG | N/A | Vector format scales infinitely, smallest file size |
| Product Images | WebP or AVIF | 85% | Balance quality and file size for ecommerce |
| Background Images | JPEG or WebP | 60–70% | Usually behind content, lower quality is acceptable |
Lossy compression permanently discards data. Once saved, you cannot recover the original quality. Always keep the original uncompressed image as a source file and compress copies for distribution.
Most social media platforms re-compress images anyway. Upload at 85% quality in JPEG or WebP for the best balance. Higher quality files will be re-compressed by the platform, so uploading smaller files saves upload time without visible quality differences after the platform’s processing.
You may have used lossy compression (JPEG/WebP lossy) on a screenshot. Screenshots with text and UI elements should use lossless compression (PNG or WebP lossless) to preserve sharp edges and text clarity.
No. All compression happens locally in your browser. Your images never leave your device.