I'm using Manga2eBook (
https://www.mobileread.com/forums/showthread.php?t=11261) to convert collections of daily comics (Foxtrot and Boondocks, if it matters) to .pdf files for transfer to my PRS-500. However, they're currently in .cbz files with one comic per page.
Are there any other programs that have the ability to combine multiple .gif or .png files onto one page of a PDF?