You can use the so-called ‘At monkey’ link to download the (source) image file having the original filename. No description however.
See Table VIC-
1 Download Link (aka Art Monkey link) Makes the photo name a download button.
1.1 Art Monkey Source Use Source file for art monkey link if available.
1.2 Art Monkey Display Select button or link ( text ).
This works on the slideshow, if the photo name is displayed. (Table II-B5), but only one photo at a time.
Alternatively, use the Photo Albums -> Export Photos admin page. This exports a .zip file of the album, that can be imported in (another) wppa installation. It contains some metadata (name, description, … ) but not everything.