MozJPEG vs XConvert Image Compressor

MozJPEG is a free, open-source library project that improves JPEG compression efficiency to produce smaller files and higher visual quality. It is intended for graphics programs and image-processing tools, and programs using the libjpeg API can integrate it without MozJPEG-specific integration code. It is compatible with the JPEG standard and the vast majority of deployed JPEG decoders. When converting other formats to JPEG, it uses trellis quantization to target the quality-to-file-size ratio. Its progressive encoding with jpegrescan optimization can losslessly reduce the size of a JPEG when used with jpegtran. The project’s improvements can be disabled at runtime, returning it to libjpeg-turbo behavior. The repository includes a demo cjpeg command-line tool, which is not intended for serious use. Build instructions cover Unix-like systems, macOS, Linux, and Windows with Visual C++ or MinGW. The GitHub repository identifies version 4.1.1 on its latest release page. MozJPEG points users to libjpeg-turbo documentation for additional build help; its repository does not state security certifications or compliance claims.

XConvert Image Compressor is a web-based tool for compressing, resizing, and converting images, with batch processing and API access. It supports formats including JPG, JPEG, JFIF, PNG, WebP, HEIC, AVIF, GIF, BMP, TIFF, ICO, PPM, EPS, and several RAW formats. Images can be uploaded from a computer, Google Drive, or Dropbox. Compression can be combined with conversion to JPG, WebP, AVIF, PNG, or HEIC; metadata controls and Auto Scale are also available. Auto Scale adjusts dimensions to meet a target file size while maximizing quality. Free users can compress images up to 300 MB each, with no per-session file-count cap. Free video conversions are also offered: visitors get 30 daily, and free accounts get 60. Basic costs $4.99 a month or 49.99 USD yearly; Pro costs $9.99 a month or 99.99 USD yearly. The service says uploads use TLS in transit and files are automatically deleted after a few hours. No account is required for the online tool, and an XConvert desktop app supports offline conversion and editing.