[itsamemarkus]

Hi, I recently noticed that a lot of my technical books (mostly humble bundles) don't have optimised pngs, which means when the ebook extracts the temporary files would be 1GB+ for a 70MB epub file.

For me that's relevant because I self host calibre web and the server has to transfer (and store) all that data when I open a book in a browser.

When you edit a book there is a "compress images losslessly" option, which is what I want and which helps with my problem. But this can only be done for one book at a time as far as I know.

There is also "ebook-polish" command line utility that comes with calibre, which basically does the same, where I could build a script that runs that for every epub and replaces the original file.

I haven't done much with the calibre database or the underlying files, I just read that you probably shouldn't touch the raw files to avoid corruption.

Can someone recommend the best way to batch polish all my epub format books? (most of the books have multiple formats available)