remove old image files

git-svn-id: https://plugins.svn.wordpress.org/dpabottomofpostpage/trunk@988078 b8457f37-d9ea-0310-8a92-e5e31aec5664
change file names to lower case


git-svn-id: https://plugins.svn.wordpress.org/dpabottomofpostpage/trunk@988082 b8457f37-d9ea-0310-8a92-e5e31aec5664