I just updated the add-on and the image editors is now working. I normally see an update prompt of plugins, this one there was not, so I am not aware of the update. I have downloaded the new version in the download page of the add-on.This issue is fixed in the latest 0.9.6 version. Please, make sure that you are using the updated version of the add-on. In case you do and you still have this issue, please, feel free to contact me, so I can help you.