Cannot test current have no PhothoShop , but alpha tranparency channel must be created - i guess -
Mostlty *gif seems to be supported in DVDA, but maybe My old macromedia Fireworks cannot export transparent *gif in needed format, not sure.

now i used Macromedia Fireworks to create new file with transparent background *.PNG (graphic) file - draw some different elements and text with defferent color and save as (PNG 8 - 256 colors, Alpha Transparency )
and inserted 'as graphic' (for menu .. ?) into DVDA this was OK -
but as i insert it as background this works also but all transprent area is black -
I am also newbie with DVDA and not find out how to change background color to blue for example, with out inserting blue image in there :(

also i guess transparent graphic could be done in PhothoShop by adding transparent (Alpha) channel and saving as *png, *gif, and also *tga files
i only suppose that PhothoSshop *gif and *tga may work - not sure cannot test currenty ...