revised caption handling and image styling.

git-svn-id: https://plugins.svn.wordpress.org/send-images-rss/trunk@988400 b8457f37-d9ea-0310-8a92-e5e31aec5664
tagging version 2.5.0

git-svn-id: https://plugins.svn.wordpress.org/send-images-rss/trunk@988402 b8457f37-d9ea-0310-8a92-e5e31aec5664