What exactly is image compression?
Image compression is the science of reducing file size while maintaining as much quality as possible. It works by identifying and removing redundant information in the pixel data.
For most websites, optimizing images through compression is the single most effective way to improve page load speed.
Lossy vs Lossless Compression
The choice between lossy and lossless depends entirely on what you prioritize: file size or pixel perfection.
Lossy Compression
Massive savings by discarding "invisible" data.
- Up to 90% size reduction
- Permanent data loss
- Best for photos and e-commerce shots
- Formats: JPG, WebP (Lossy)
Lossless Compression
Zero quality loss, 100% data preservation.
- 20–50% size reduction
- No quality reduction
- Best for logos and text graphics
- Formats: PNG, WebP (Lossless)
Compression by Image Format
| Format | Compression | Transparency |
|---|---|---|
| JPG | Lossy | No |
| PNG | Lossless | Yes |
| WebP | Both | Yes |
| AVIF | Both | Yes |
For modern web use, AVIF is the efficiency king, often outperforming WebP by 20%.
How to compress your images
You don't need expensive software like Photoshop to compress your files. Use our free, in-browser tools:
- Universal Image Compressor — Drag, drop, and save.
- KB/MB Target Optimizer — Great for official portals requiring under 100KB.
Frequently Asked Questions
Is compression the same as resizing?
No. Resizing changes the pixel dimensions (e.g., 1000px to 500px). Compression changes how those pixels are stored. You should ideally do both for the best performance.
Will my images look blurry?
Not if you use a quality setting above 75. Most humans cannot tell the difference between a 100% quality JPG and an 80% quality JPG, even though the 80% version is much smaller.