This makes me want to play Capcoms Avengers! It makes me feel good. :)

Yeah, that's what I meant by having a propre four frame walk and a seperate idle sprite rather than just a 3 frame one like this. Now that I look at it though, for the three fram I should have made the toes point more inwards. =/
 

Hopefully I can find time to do the other two proper between frames rather than that one dodgy middle frame. XD

the middle frame looks wierd because the feet are sideways.  IF you want to keep this number of frames, I would experiment having the middle frame such that one foot is slightly in front and the other slightly back.  Then mirror the frame the 2nd time.  This way each foot passes through 4 positions, rather than 3, using the same number of unique frames.  Though, since you can see the full legs here, maybe the middle frame can be used to show one foot lifted off the ground or something.  Same can be done with the arms, though I dont really have an issue with them here.