Attachment Link Works, Image Link Doesn't

I’ve come across a case where the attachment link works, but the image link doesn’t.

Ex:
Works: http://www.pittsburghfrugalmom.com/?attachment_id=13288
Doesn’t Work: http://www.pittsburghfrugalmom.com/wp-content/uploads/2012/10/Koala.jpg

I suspect it might be a permissions issue on the upload folder but don’t have server access yet.

Any other ideas as to what might cause the issue?