I'm coming across this same issue.
I can confirm that the pictures listed in my import file are present and accessible.
I receive no errors when uploading the import.
The images do not show in either the front or backend.
I have disabled cache (left off), disabled friendly urls (tested but no difference so turned back on) but still no pictures.
Any help on this would be great, before I move on to my next task.
As per
I've editted and removed www from my domain names. This has still not worked.
I imported the products again just in case, deleting the old products, no change.
Manually adding a product image from the BO works fine.