Onion Skinning with Background Image Problem

Hi. I’m working in the 2D Animation to draw a cartoon. I’m projecting a Background Image through the Camera, just for reference, but there’s one problem. When I insert a keyframe and adjust the opacity of the Onion Skin, instead of showing the background image, what i see is the World Background color. This is problematic, because the onion skin ends up blocking the reference image.

How do I fix this?

Thank you!

Pretty sure i figured it out.

Camera > Background Image > Depth
change from Back to Front