Rewrite djblets_images tags to use storage backends.
Review Request #1078 — Created Sept. 16, 2009 and submitted
Rewrite djblets_images tags to use storage backends. When I wrote these utilities (cropping and thumbnailing), I didn't take into account that Django provides a storage abstraction. The default storage is on the local filesystem, but there are third-party backends that also work. This change updates them to use the storage APIs instead of working directly with file objects on the local disk. This change is in preparation for a corresponding review-board change to allow the use of django-storages backends (specifically Amazon S3) for screenshot storage.
Tested screenshot thumbnailing against screenshots stored in Amazon S3