[patch] repair _get_image_dimensions
|Reported by:||Owned by:||Adrian Holovaty|
|Has patch:||yes||Needs documentation:||no|
|Needs tests:||no||Patch needs improvement:||no|
Following up to #1858, _get_image_dimensions and _get_FIELD_filename are called inconsistency from a few places. This patch fixes the magic get_IMAGE_height and get_IMAGE_width accessors.