Looking at them from the shelf, I would line them up Thor then Cap then Hulk.
Thor's right arm flanks the left side and Hulk is looking towards the right. Right now it looks like Hulk went crazy and is about to rip Cap's head off.
It looks like Thor is deliberately holding his hammer up to distract Cap from the fact that he's about to be sucker punched into next week by the Hulk. Marvel Team-Up *******s.
The scale does seem a bit off in that pic though. Cap should be closer to the Hulk's height (and assumedly Thor's as well) as this pic from Squider's fantastic collection shows: