Process Flow Images - No Select/Tree Properties

I've added some images to a PF Model to aid the understanding with the client, I want to make them no select so that I can avoid moving them by mistake but there isn't an option for that. I also can't find the link to the image in the tree either. Can anyone help with that??

Hi,

the only way I found is to untick the "Fill" option of the picture. This changes the function so you only can select the picture if you hit the frame, what should be fine for large Pictures in Background.