I have a real puzzle on my hands with thumbnails generation with showthumb.php.
Check out my example here;
www.tjauto.no/solgtebiler/item/10-chevrolet-corvette-c5-cabriolet
Some thumbs show, some don't. If you reload, it's never the same images - seems totally random. If you rightlick the red cross (x) in IE, and select "Show picture", the thumbnail will show.
Sorta seems the thumbnail generation is not quick enough, and IE displays a red cross since it doesn't receive any imagedata in the time it has allocated to wait.
Due to this I'm pretty certain it's not an issue with permissions, filetypes or filesizes (altho filesize will increase load and time spent on the resizing).
Any suggestions? I found one post about this exact same on these boards, but from way back in 2008, and it had no solution posted.
Solutions will get some PayPal bucks!