Nice job on this module, congratulations.
A few suggestions re usability features... in order of relative importance (imho)

1) I think the most important bit is an option (checkbox) on the config page to include the quantity field... would be nice if it was independant of the add to cart button for max flexability (obviously you would not want the qty field to be displayed without add to cart, but some users may like it as is now - add to cart button only)

2) perhaps another option to tighten up white space (minimize the padding on top & bottom of rows)

3) adjustment of grey border line (perhaps an invisible border option) or ability to define a hex colour of the border line... then admin can make it same colour as background to make it invisible.

4) a bit of ajax so when you hover over an image it shows a floating full size image (a check box option in config would toggle this functionality on/off)...(homedepot.ca does this.. clever use of ajax)

again great job...well done.... down right uberlicious