I see some people having trouble finding reference pictures so I uploaded everything I used onto a photobucket album! Hope it helps.
I have a lot of movie stills and other random tumblr pics, the pictures of the really realistic and well done (not to mention expensives…) Loki figure Hot Toys made which is pretty accurate to the movie original costume. I think I have a picture from wyrdsister who also did an awesome loki from Thor version and is currently working on the avengers version. =]
I do have to say though, there are times where his armguards are actually DIFFERENT although he wears the same costume. Same goes for the sleeve ends that are shaped the same way as the armguards. In one, the back of the armguard that wraps around his arm comes off the MIDDLE of the armguards, but in another it comes off the END of the armguard near his elbow, but more often than not it comes off the middle of the armguard.