[Plugin: NextGEN Gallery] Imagebrowser & Singlepic: get dynamic url

Hi there.
I am using NextGEN 0.92. I want to add a link to both my imagebrowser page and a single post where the user can click on to download the image instead of clicking on the image itself. Therefore, I would need the php expression to get the url of each pic dynamically. I have been looking in the code, but could not find the variable of how to the the full url to a pic while in imagebrowser mode (same for post where the pic is shown as singlepic). Any suggestions?
Thanks dudes!