Adding a image at the bottom of a message (Float left) overwrites the bottom of the message container.

Create a message and add an image float left at the bottom so that the image bottom is below the last line of text.

Like this one: http://next.dev.curriki.org/xwiki/bin/view/Messages_Group_AthabascaUnivercity/StartingaNewCourseProject-SeekingVolunteersforAesthetics

Notice the image goes below the bottom of the message area.