Disneyscreencaps.com features thousands of screen captures from shorts, features, and made for DVD films. It also includes work from Pixar and Dreamworks.
I don't know if there's any rhyme or reason for the particular captures. It doesn't appear that they were selected by an animator. For all I know, the captures were done by an automated process. In any case, if you're looking for a handy visual reference from any of the films they've covered, it may be quicker than hauling out the DVD.