Hello j2aircraft,

The best way to do what you want is to set the image then edit it by clicking the Edit Image button.  Once the image editor loads up, use the eyedropper to set the magenta color as the current foreground color and then click the color eraser tool.  Using the color eraser, erase all the magenta from the image.  Next, close the image editor and apply the changes.  If you've done it properly, you'll see that the image background is transparent.