Create a new account
A submit button (or any image used instead) SHOULD NOT have a "name"
attribute, unless the form contains multiple submit buttons.
Firstly it's a extra thing you don't need, secondly it makes the resulting URL (if you use GET) much nicer (no image.x/image.y params).
You're supposed to use GET for any request that doesn't change anything, eg. search results. See:
Get More Comments