Connect-A-Sketch – Upload and Connect Your Sketches To Create Clickable Prototypes
http://connectasketch.com/

There are a thousand great design tools out there, including pen and paper. Sketch out your designs, then upload them to Connect-A-Sketch. Drag and drop your sketches into your prototype. Create connections between sketches and make your prototype interactive. Explore your own interactive design, or easily share it with your users.
Features include: a) Free; b) Upload jpg and png files; c) Test out ideas quickly and easily; and d) No need top re-create your designs. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog. This will be added to Entrepreneurial Resources Subject Tracer™.