I made a camtasia clip with 15 photographs, I successfully added a watermark, bur I don't want this watermark to be visible on the first and last photo of my presentation. . An option to make this possible would be nice to have.
In case you haven't found a workaround, you could insert the watermark image as a layer on your timeline that is above all other layers. That way you could precisely choose the duration it is presented.