alphagov/whitehall — pull request #1061 by layam (2013-11-15 15:01:55+00:00)
Title: Consolidate image validation into ImageValidator

Image validation, especially the validation of image size
was repeated all over the place. This adds a validator class
to cover both validating an image is readable, that it's mime-type
matches the file extension and that it is of the correct size.

Removes ImageSizeChecker.

Fixes: https://www.pivotaltracker.com/story/show/44008053