Customized submission form

Hi,

I am happy to use gallery 2.3.

I want to make a custom form to add items.

I just want to know if it is possible by modifying code (simple modification, not rewrite all core files...) to add 1 album and 2 pictures in this album with only one form (one click on save button).

If it is possible, could you tell me what are files (inc and tpl) to modify to change form?

thanks