Don’t forget you’ll need to make this change after each NextGEN upgrade unless you’ve created your own custom template
If you copy the template file to (your theme dir)/nggallery/ NextGEN will use that, and it won’t be replaced when upgrading NextGEN.
I don’t think there is a way to make singlepic load anything other than individual images. It’s a bit cludgy but the following should work:
[ngg_images image_ids='1,2,3,4' order_by='rand()' display_type='photocrati-nextgen_basic_singlepic']
