Compress Image

Image Compression for the Web

Large images are the most common reason websites load slowly. An uncompressed photograph straight from a camera can weigh 5 to 15 MB, far more than any visitor wants to download just to see a blog post or product listing. Image compression reduces that file size so pages load faster, use less bandwidth, and rank better in search engines.

Lossy vs Lossless

There are two broad approaches. Lossy compression discards some image data that the human eye is unlikely to notice. JPEG is the most familiar lossy format: by adjusting the quality parameter you control how much data is thrown away. At a quality of 80, most photographs look nearly identical to the original while being 60 to 80 percent smaller. Drop the quality to 40 or 50 and the savings grow further, though you may start to see artefacts around sharp edges and text.

Lossless compression keeps every pixel identical but rearranges the data to take up less space. PNG uses lossless compression by default. The savings are more modest, typically 10 to 30 percent, but the image is bit-for-bit identical when decoded. WebP supports both lossy and lossless modes and generally produces smaller files than either JPEG or PNG at comparable quality.

How This Tool Works

This compressor runs entirely in your browser using the HTML Canvas API. When you load an image, it is drawn onto an off-screen canvas at full resolution. The canvas is then exported as a JPEG at whatever quality level you choose. Because JPEG is inherently lossy, even a PNG source image will be converted to lossy JPEG output, which is normally what you want for photographs destined for the web. Transparency is replaced with a white background.

No data leaves your machine. The image is never uploaded to a server, so there are no privacy concerns and no file-size limits beyond what your browser can handle. For most images under 50 MP the process takes less than a second.

Tips for Best Results

Start at quality 80 and compare the result visually. If it looks fine, try 60. For hero images or portfolio work, 85 to 90 strikes a good balance. Icons, logos, and illustrations with flat colours are better served by SVG or optimised PNG rather than JPEG compression. Always check the output on a retina screen if your audience uses one, as compression artefacts are more visible at high pixel densities.