I have experienced a similar problem this afternoon. My host was able to disable the plugin so we can now access the our site publicly and through the WP administration login page. When I attempted to update the plugin I received the following error message –
Fatal error: Allowed memory size of 306184192 bytes exhausted (tried to allocate 20480 bytes) in /homepages/28/d121196907/htdocs/clickandbuilds/GreenMountainRegionPCA/wp-content/plugins/photo-gallery/framework/BWGOptions.php on line 330.
Any suggestions are most welcome.