Compress CBR/CBZ comic files by 50 percent or more
Digital comics often come in the form of comic book archives, typically JPGs stored in a single archive file (cbz = zip, cbr = rar, and so on).
You might think these simple compressed formats would already produce the smallest possible files, but no -- the free CbxConverter can resample images and convert them to WebP, shrinking the archives even further.
The program is barely a 1MB download, and doesn’t require installation -- just unzip it and go.
The default JPG > WebP conversion delivered reasonable results in our eight test comics, which fell to a fraction less than half their original size, without a significant reduction in quality.
If you choose to resample the image then there’s scope to achieve much more. We set the resize/ resample option to 50 percent and our file sizes dropped by 83.3 percent.
Once you get past the core conversions, CbxConverter’s interface becomes annoying. Even a basic task like clearing the source file list isn’t straightforward. There’s no "Clear" toolbar button, no menu option, you can’t select them and press Del -- the option you need is available on a right-click menu only.
CbxConverter carries out its main function well enough, though, and if you need to batch process a group of comics -- and your comic reader can handle WebP files -- then it just might be good enough.