Cannot edit settings after inserting image html

I tried to add an html tag for an image I wanted to insert in the announcement text, but I am now unable to edit any of the options related to the plugin. I’ve tried deleting the plugin and re-downloading it and that did not work. I also tried to download an old version of the plugin but that did not work either. The settings are saved every time and I am unable to make selections in the plugin settings to remove the html. It seems like it broke the plugin, but I don’t know how to fix it.

http://wordpress.org/extend/plugins/genki-announcement/