I get this error:

Sorry, file '/Users/sgiessle/Pictures/iPhoto Library/Modified/2006/2006_04_29/IMG_0300.JPG' is not readable (permission issue)

Only for images that wipha finds in the "Modified" folder of my iPhoto Library. For some reason certain images are displayed as thumbnails which point to this folder instead of the originals. And this iPhoto by default uses a different permission scheme for this folder. Specifically, permissions are:

-rw------- 1 sgiessle sgiessle 1358265 May 3 17:43 IMG_0299.JPG
-rw------- 1 sgiessle sgiessle 1438904 May 3 17:43 IMG_0300.JPG

I'm not certain how wipha works, but it seems like the files not being world readable is the problem. If I manually change them (chmod 644) then it works, but this will not prevent the problem from happening again in the future when new "Modified" images get created. One thing I am puzzled by is - what is the "Modified" folder for? I did not modify the images that are in there. iPhoto must have done this automatically for some reason.