Image Compressor

Lossy image compression reduces file size by discarding visual information that the human eye is least likely to notice. JPEG and WebP encoders divide the image into blocks, transform them into frequency data, and quantize high-frequency detail away. Lower quality settings discard more aggressively, producing smaller files but introducing visible artifacts — blocky edges, color banding, and smearing around text. This image compressor online tool uses the browser's built-in Canvas encoder, which implements the same algorithms used by professional image editors. To analyze how compression affects your image at the pixel level, try the ELA Scanner or JPEG Ghost Scanner.

Drop or select up to 50 images and the tool processes them all with the same quality, target size, and format settings. Each file is compressed sequentially in your browser, with a live progress row showing the original size, compressed size, and percentage saved per image. When everything finishes you get a one-click ZIP of every compressed file, plus individual download links if you only want some of them. Because compression runs locally — even in batch mode — none of your images is ever uploaded to a server, and the page works on slow connections or offline once loaded. For batch resizing alongside compression, pair this with the Image Resizer.

Many platforms enforce file size limits — email attachments, form uploads, social media profile pictures, government portals. Instead of guessing quality levels, the target size mode automatically finds the highest quality that fits within your limit. It uses a binary search algorithm, testing up to 12 quality levels in under a second. In batch mode the same target is applied independently to every image, so a folder of 30 photos can all end up under 200KB in one click. If the target is unreachable even at minimum quality, the tool suggests combining compression with resizing via the Image Resizer — reducing pixel dimensions before compressing is the most effective way to hit very small targets without destroying visual quality.

JPEG is best for photographs — it achieves high compression ratios on natural images but does not support transparency and introduces artifacts at low quality. WebP typically produces 25–35% smaller files than JPEG at the same visual quality and supports transparency, making it ideal for web use. AVIF pushes compression further still — often 30–50% smaller than JPEG — but encoding is only available in Chromium-based browsers (Chrome, Edge); unsupported browsers will fall back to PNG. PNG is lossless — it preserves every pixel exactly but produces much larger files, so it is best for graphics, icons, and screenshots with sharp edges. This photo compressor lets you switch formats and compare the results. To inspect compression artifacts forensically, use the Quality Analyzer or examine the JPEG Structure of the output.