Changing attach BB code style?

[TheDPQ]

I can't seem to find this anywhere. I noticed when i use the [attach] bb code (3.5.3) that it gives me something like style=margin:2px Where is that being set?

Is there a way to add a class=thumbsattach to the line the BB code generates?

Also, is there a list of options that this bb code supports? I just noticed the attach=left is there anything else it supports?

Thanks for your help.