How to reduce ZIP size
Recompression helps when an archive contains highly compressible data.
Files that usually compress well
Plain text, logs, CSV, JSON, XML, HTML and source code often contain repeated patterns.
Files that usually do not shrink much
JPG, PNG, WebP, MP4, MP3, many PDFs and existing ZIP files already use compression.
Remove system metadata
Files such as .DS_Store, Thumbs.db and __MACOSX folders can be removed from a shared archive.
Compress source files first
When the ZIP contains large photos or PDFs, reduce those files before creating a new archive.