Originally Posted by sarah_pnix
I'm also experiencing the same problem as the OP. I'm converting epub to mobi using Calibre. I've done many books this way and never had a problem. In the debug folder, everything looks fine. It shows up fine in the Kindle Previewer app. But on the actual Kindle, some of the images display strangely, exactly as described. Here are photos so you can see what we're talking about.
I'm going to try converting my jpg images to png as John123 suggests.
This is a Kindle display problem, (obviously!) not a Calibre problem. If you go into Photoshop (File Menu>"Save for Web & Devices") and save all of your jpegs with this step it will completely solve your problem. Just do this as your last step before converting to .mobi in Calibre. You can just batch automate the entire "images" subfolder.