Create an image Widget on the HUD. Bind the “Brush” of the widget to a variable of type “Slate Brush”. Then use the Download Image node to set the variable.
Or you could save the texture2D to file and then load it whenever you want. I prefer to set the image from the URL, this way it is up to date if the user changes their FB image. Take a look at Rama’s Victory plugin, he has a lot of awesome utilities for images:
