For this test, the Mac port paints a black background when partially loading PNG images that have no alpha. A green background is expected. Synopsis: the image frame containing the decoded image should be 1) initialized with transparent black rgba(0,0,0,0) and 2) marked as having alpha channel until the image if fully decoded. Partial loading implies partial decoding, so this test reveals the state of the image frame before the image is fully decoded to see if conditions 1) and 2) are upheld.
I think this test started passing after http://trac.webkit.org/changeset/150340 ?
Created attachment 202774 [details]
Created attachment 203409 [details]