Author: Brendan Heywood
MDL-70368 files: Cache image dimensions
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fe88783c0f2d401026d9344af12d011212b58843
http://github.com/moodle/moodle/commit/fe88783c0f2d401026d9344af12d011212b58843
+ 4.1 en [cachedef_file_imageinfo,core_cache]