This fixes the xcf test that was failing, i guess at some point someone
run optipng or something over the expected result and that was causing
the test to fail
image formats are loaded via qimage/qimagereader and friends, the user/developer does not choose which ones will be used so giving him a warning about sequential devices not being supported is not going to help anyone, only spam their shell/logs.
REVIEW: 123156
Acked by David Edmundson