Free image compressor that works entirely in your browser — no file uploads, ever. All compression runs locally via WebAssembly (MozJPEG + libwebp + OxiPNG). Supports JPEG, PNG, WebP & GIF. Batch compress multiple files. Drag, drop, download. No sign-up, no limits, no watermarks. Free forever. Perfect for developers optimizing assets or anyone who values privacy. 8 languages available. Most "online compressors" upload your files to servers. CompactJPG doesn't.