
Thats odd, anyone else having problems with the pictures. They are fine for me. 
There are quite a few that are rotated 90 degrees left or right (am viewing on an iPhone).
I'm guessing that the rotated images were originally taken on an iPhone as portrait then edited on said iPhone by cropping for length and rotating, then uploaded. When viewed on a PC they'd look fine but I believe that as the image file still contains the original data when viewed on a iPhone they'd present with the original portrait alignment. Something like that.
To get round the problem you have to 'fix' the edited image (by removing the image's edit history), which I believe is what happens when you save the edited image in an app, or email or message it.