wimlib is an open source, cross-platform library for creating, extracting, and modifying Windows Imaging (WIM) archives. WIM is a file archiving format, somewhat comparable to ZIP (and many other file archiving formats); but unlike ZIP, it allows storing various Windows-specific metadata, allows storing multiple "images" in a single archive, automatically deduplicates all file contents, and (recently) supports optional solid compression to get a better compression ratio. wimlib and its command-line frontend wimlib-imagex provide a free and cross-platform alternative to Microsoft's WIMGAPI, ImageX, and DISM.