Generally, I don’t like links with buttion functionality, like submitting a form, so to me it isn’t an option.
When it comes to the two other alternatives, there aren’t any easy answer to it. It can be a design issue, when creating your own images can everything look so much better, you know they will look the same in ll web browsers etc.
However, something I find confusing is when designers (usually Mac users themselves) create a design where the buttons just look like the buttons in Mac OS X, which there is nothing wrong with, but it feels weird when you have a design where you have to use images for buttons when they’re just a rip-off of built-in system buttons from another operating system.
If one is going to use images, I ask for more creativity, please.
But when it comes to the recognization factor, I lean towards using the built-in system buttons, since those buttons look like they do in most web pages for the user, and they look like the buttons the user is used to so he/she doesn’t have any problems finding what button to click.