Allow read Image to be saved as Initial value

[ScottRobson]

With V6 Surface Automation, we often want to be able to spy 2 states of a Co-Ordinate region, eg: a radio button selected/unselected.

The 'easiest' way to do this whilst developing, is to:
1) Read the image in the state you want it
2) Export that variable to a .png file
3) Import that .png into the Initial Value of the Image data variable.

 Would be nice to have a button to save the output of step 1) above, directly to the Initial Value of the variable, to save the messing round with creating a temporary .png file.