Also refreshes and fixes some of the unit tests for media, and replaces test-image-large.png with test-image-large.jpg which is larger to allow testing of `original_image` in the image meta.
Fixes#50628.
git-svn-id: https://develop.svn.wordpress.org/trunk@48454 602fd350-edb4-49c9-b593-d223f7449a82
Andrew Ozz