Would like jquery lightbox plugin to sit in my page with no white background

Q: I'm trying to incorporate the jquery lightbox plugin into my website.
I am using the way of only showing one thumbnail & I would like this to
sit in my page body on it's own with no white background so that the finished page
will show my whole website's main background.

Can you please let me know how to remove this so that the white background doesn't
overwrite my main template background which is an image.

A: You should do the following:

open Gallery->Properties->Thimbnails: Thumbnails format,
select 'PNG' format from the drop down list.