Yes, it is a great idea. I wonder if the image could be selected in a way that fits with the topic of the day. The ensuing discussion could be a bridge into the lesson. Making Thinking Visible (Project Zero) and visual thinking (http://www.vtshome.org/research/visual-thinking) are great strategies to get students to think creatively.
I like this idea very much. It puts students into the positive emotional attractor (Boyatzis et.al.) by having to think about and identify behaviors that get them to imagine a different or desireable state...one that aligns with an Ideal Self.