Now this is nothing particularly fancy nor clever. I just needed the shape for myself and thought I'd share it.
Having had to annotate a picture, I realised - that while not really difficult - there's a big amount of adjustments to make a proper annotation shape.
It needs to stand out in front of the picture. Therefore you need a custom line pattern with a larger contrasting background.
You need also different line ends (arrows and dots), with the same contrasting issue as the line itself.
And while drawing, you notice that all your annotation angles are different and look ugly, so you set up a custom property to get them all equal.
Distributing the annotations is also easier when they are 2D shapes. Visio's 1D shapes whilst nice are more difficult to arrange.
Now I needed an example and googled "the most famous picture". The oscar's selfie of 2014 seemed to be a good example, but there were too many "heads" to annotate. So I googled this as well and got the list of the actors.
Favouring coding over typing I set up a small tool to generate automatically the annotation shapes with the right text from the list. Try it out by running the macro "showSplitform". This tool can also be used for other purposes - ie: whenever you need to distribute a text over single shapes.
I hope this can be of use for someone. Enjoy,
Yacine
PS: more important than all the smartshape magic, is the tip to add connection points to the picture and then to lock the picture against everything, but the selection (for setting the connection points).