I don't see anything that supports the idea that the image is propaganda. Is the image with the red line trying to suggest that the group photographed in the top left is the same as the executioners(?) in the top right? If so, I don't see it. The people connected by the lines really don't look similar to me.

That's not to say the image hasn't been propagandized. I'm sure it has. Its a useful tool for anyone trying to turn people against the Syrian government. But that also doesn't mean it was created as propaganda.

Its easier to co-opt an organically born symbol than it is to build one out of thin air.