A lot of times shrinking can distort a picture. I guess it depends on what you use to reduce its size and how much you do shrink it.
Try to 'edit' you picture and see if there is something you can adjust there.
Also, make a backup it so just incase something goes wrong, you have another one.
Also, if this happened right when you logged in, that can play tricks on you. If the info for the target isn't updated to you it might show up as a Bishop when in fact its a Rook. I think this might be whats happening. Ever notice if you log in at a busy field with a large number of people in the arena, sometimes a plane will be taking off and it has the field guns firing at it. All of a sudden when its information gets updated it changes and the field guns stop shooting at it.