single post – image size

i thought the resized image size for single blog post images are 727 x 285 (which all of my “old” imported are).

but every new post has 727 x 727. 

any change that i can change this?

OK – http://www.themashup.org/je-veux-du-hard-dj-athom/

WRONG – http://www.themashup.org/indila-derniere-danse-freddy-verano-edit/

THX

Vodoo76