'I assume you mean without doing a custom crop for each image--that is using some sort of default crop but with more of the image.' - actually not with more, but with less of the image that it could.
i want the crops to be 247 x 180 and so had the thumb size set to 247.
playing around with the thumb size i noticed that at 100 it works the way i want but with obviously bad quality - its upscaled to be 247 x 180 in the gallery.
here is the options screen:
'http://www.superoforma.com/o.jpg'
thumb size of 100, uses max possible image area to generate thumb (good)
'http://www.superoforma.com/1.jpg'
thumb size of 247, doesnt use max possible image area to generate thumb (bad)
'http://www.superoforma.com/2.jpg'
same happens with 200, 246, 250 as with 247
hope its more clear now