REQUEST: Download image with a mouse button or gesture

[BurrowBird]

Would it be possible to add a mouse gesture or shortcut (e.g. pressing the mousewheel) to download the zoomed image instead of "S"?

EDIT: Tried several remapping solutions but failed. I wanted to use the middle mouse button but not lose the normal functionality of it (closing tabs etc.). Ultimately I ended up using a program "X-Mouse Button Control", with a function called "Button Chording", where I mapped the RMB + MWheelDown combination to "s" (which is my download button in Hoverzoom). Not ideal, but kind of works. Maybe I should get a mouse with more buttons.