title_body: How do I make Calibre convert CBZ to EPUB without images shrinking or conversion? I've got comics in CBZ format with pictures in 2k or 4k pixels tall and when I try converting them to EPUB, Calibre shrinks the pictures to 1k or under, making them very blurry to view on a mobile or tablet.  Is there a setting or type of script I can use to convert each picture to its own EPUB page and not have Calibre shrink the picture?
upvoted_answer: Try Kindle Comic Converter.  Despite its name, it works for all types of readers, and can output EPUB.  Be sure to select the generic reader output, enable Color Mode, and select EPUB as the output format.