bzip2 vs FileOptimizer

bzip2 is a free data compressor for creating and reading compressed files. It provides command-line tools and supports BZ2 (.bz2), BZ (.bz), TBZ2 (.tbz2), and TBZ (.tbz) formats. The maker says its compression typically comes within 10% to 15% of the best available PPM-family techniques, while running around twice as fast for compression and six times faster for decompression. Its limited media-error recovery may allow undamaged portions of a damaged file to be decompressed. The separate libbzip2 library lets programs read and write .bz2 files or compress data in memory. Command-line flags resemble GNU Gzip's, and the distribution should compile without modification on Unix and Win32 systems. bzip2 dates to 1996 and is open source under a BSD-style license. The official site lists version 1.0.8 as stable and offers source code, not executables. Building has a good chance of success with an ANSI C compiler and at least 8 megabytes of spare memory; the source tarball includes documentation in several formats.

FileOptimizer is a free Windows program that recompresses already-compressed files to reduce their size while retaining their format and behavior. It supports batch processing and accepts files through its interface or command line; optimization replaces them with optimized versions. The maker says it handles more than 600 file extensions and identifies types by examining file contents, regardless of extension. Listed formats include APNG, AVIF, BMP, BPG, DDS, DNG, GIF, HEIC, HEIF, ICO, J2C, J2K, JP2, JPEG, JPG, JXL, MNG, MPO, PCX, PNG, PSD, SVG, TGA, TIF, TIFF, and WEBP. By default, it removes extra metadata and keeps originals in the recycle bin. The program includes more than 90 third-party tools as plugins and supports command-line automation. It is provided under the GNU Affero General Public License, free for personal and commercial use without feature limits. The maker lists Windows XP through Windows 11 and Server 2022 among its requirements. Lossy options are also documented for PNG, JPEG, and GIF.