How to Compress Images Without Losing Quality
Image compression is a balancing act: smaller files load faster, but push too hard and quality collapses. This guide explains how to get the size down without the eye noticing.
Lossy vs lossless compression
Lossless compression rebuilds the exact original image on decode — nothing is thrown away. PNG and WebP-lossless are common examples.
Lossy compression permanently removes information the eye is unlikely to miss, producing far smaller files. JPEG and standard WebP are lossy.
Choosing the right format
- Photos and complex gradients: JPEG or WebP at 70–85% quality.
- Screenshots, diagrams, flat colours: PNG or WebP-lossless.
- Modern web with fallback: WebP first, JPEG or PNG as backup.
- Icons and logos with sharp edges: SVG when possible.
Finding the right quality setting
For most photos, quality between 70 and 82 produces files roughly a third of the original with almost no visible loss. Above 90 the file grows rapidly with negligible gains.
Always look at compressed images at their actual display size. Zooming in exaggerates artefacts you would never notice in real use.
Resize before you compress
The biggest gains often come from resizing. A photo displayed at 800 pixels wide does not need to be uploaded at 4000 pixels.
Downscale to roughly the size at which the image will actually appear, then compress. You keep every pixel of visible detail while shrinking the file by an order of magnitude.
Use browser-based tools when possible
Uploading personal photos to random compression sites is a privacy risk. Browser-based compressors do the work locally, so your images never leave your device.
ToolFerry's Image Compressor is a good default — it runs entirely in your browser and shows before/after sizes.