Bought an EPUB from lulu.com and opened it in Sigil. All the images were represented by a little blue square. I checked the images folder and there was just one file called sample.jpg. So I imported the EPUB into Calibre and used the tweak function and all the proper images were in the images folder as well as sample.jpg. So I regenerated the EPUB and when I opened it with Sigil it was the same as before, no images. I opened it with ADE and all the images were there!
