How to compress images without losing quality
A smartphone photo easily weighs 5–10 MB. Multiply that by dozens of images and your emails bounce, your site slows down, your storage fills up. This guide shows you how to reduce image file size by 60–80% in a few clicks.
Why compress your images?
- Faster web loading. Google recommends images under 200 KB for a good PageSpeed score. An uncompressed image can weigh 20 times more.
- Emails delivered. Most email services limit attachments to 25 MB. Five uncompressed photos and you've hit the ceiling.
- Optimized storage. On iCloud, Google Drive, or your local disk, compression lets you store 3–5 times more files.
- Easier sharing. WhatsApp, Slack, Discord… platforms aggressively recompress your images. Better to do it yourself with controlled results.
Lossy vs. lossless compression
There are two fundamentally different approaches:
Lossy
Reduces size by 60–90%. Removes details invisible to the naked eye. Perfect for web and sharing. Formats: JPG, WebP.
Lossless
Reduces size by 10–30%. Preserves every pixel identically. Useful for archiving or printing. Formats: PNG, WebP lossless.
Filzy uses optimized lossy compression: the engine automatically finds the best trade-off between size and quality for each image.
Tutorial: compress images with Filzy
Choose your tool
Go to Compress JPG, Compress PNG or Compress WebP depending on your image format.
Drop your images
Drag and drop your files into the zone, or click to browse. You can select multiple files at once. Filzy handles batch processing.
Adjust quality (optional)
By default, Filzy compresses at 80% quality – the best trade-off for most uses. You can go down to 60% for lightweight web images, or up to 95% for editorial content.
Start compression
Click "Compress". Processing happens entirely in your browser. No file is sent to a server. You'll see the reduction percentage for each image.
Download your files
Download compressed images individually or as a ZIP archive if you have several. Original files remain untouched.
Tips for better results
- Photos. JPG format at 75–85% quality offers the best ratio. Below 70%, artifacts become visible on gradients.
- Illustrations and screenshots. Prefer PNG for images with text, sharp lines, or transparency. PNG compression is lossless.
- Modern web. If your site supports WebP, convert your images to WebP: 25–35% lighter than JPG at equivalent quality.
- Oversized dimensions. A 4000×3000 px photo displayed at 800×600 px wastes 96% of pixels. Resize before compressing.
Your files stay private
Filzy compresses your images directly in your browser. No file is sent, stored, or routed through our servers. Processing is instant and 100% local.