CBZ and CBR comic cover thumbnails in Windows Explorer

What you see

• Pages are sorted the way people number them, page 2 before page 10. The front cover is preferred, back and variant covers go last, and junk such as __MACOSX folders and Thumbs.db is skipped.
• CBR files are opened with a pure-Rust RAR reader, so nothing from WinRAR or UnRAR is needed.
• A very large comic is never loaded whole. For a CBR, SageThumbs walks the entry headers and reads only the cover.

Limits

• In OneDrive and other synced folders, files stored on the PC get thumbnails as anywhere else. Online-only files are left to the cloud app, since nothing is downloaded just to draw a thumbnail.

More you can do

• Right-click a set of images and choose Combine into CBZ to make a comic: pages are sorted by name and a ComicInfo.xml is added, so Kavita, Komga and YACReader read its details.
• Plain .zip, .rar and .7z archives get thumbnails too: by default a collage of up to four images from inside, or a single cover.

Extensions this covers

See every format SageThumbs 2K supports or browse all format guides.

Thumbnails not showing?

• Windows caches thumbnails, and a file it failed on once stays failed. In SageThumbs, Settings ▸ Advanced ▸ Rebuild thumbnail cache clears the cache and restarts Explorer.
• Make sure File Explorer's "Always show icons, never thumbnails" option is off, and that the format is ticked in SageThumbs Settings ▸ File types.
• Run st2k doctor in a terminal. It only reads, checks the whole chain, and prints a fix under anything that is wrong.

Related guides

• EPUBEbook covers, read straight out of the book.
• MOBI and AZW3Kindle-format book covers: MOBI, AZW, AZW3 and PRC.
• DjVuScanned books and documents, shown by their first page.