Image problem in wp user frontend

I’m using an artisteer theme for my website. I’m having problems with this plugin: http://wordpress.org/support/view/plugin-reviews/wp-user-frontend
The problem is if I create a new post/page with an image (say image1)everything is fine, but later on if I replace that image1 by image2, then I see thumbnail versions of both image1 and image2 show up at the bottom of the page due to this plugin. After disabling this plugin, things are fine. I want to fix this issue, any help would be appreciated..