Failures in gdiplus tests are caused by broken code in gdiplus, in particular GdipCloneImage() is broken. First, it calls IPicture_SaveAsFile() with 'mem_copy' parameter set to FALSE, and according to the tests IPicture_SaveAsFile() always returns E_FAIL in that case. Second, IPicture_SaveAsFile() has never been writing correct data to the provided stream, so despite that it hasn't returned an error the result just couldn't be correct. It looks like whoever has written that code hasn't tested it at all.
Really, gdiplus code shouldn't be using IPicture at all. We should instead use gdi32 metafile handles directly.