If ever there is an "ERROR" loading an image, e.g. "unknown image type", every subsequent image load will not display, even despite reporting "SUCCESS" in the load operation.
Ouch, that's bad. This must have been a bug for quite a while. Thank you very much for reporting it -- should be fixed now on latest master. I'll push a hotfix release soon.
If ever there is an "ERROR" loading an image, e.g. "unknown image type", every subsequent image load will not display, even despite reporting "SUCCESS" in the load operation.