This is very weird. I have a new PowerMac running Tiger and the latest version of iPhoto. When I try to add the JPEGs from my previous iPhoto library folders to the new iPhoto, using the 'Add to Library...' function under 'File', I get a message saying 'the folowing files could not be imported (they may be an unrecognized file type or the files may not contain valid data). This doesn't make sense. Those JPEGs are totally normal. Can anyone help?