Creating a cardboard cut-out OR How do I make my geometry respect my 2d image import? I'm working on a (fun but needlessly complex) mockup for my wife's work. The idea I've had is that I can use my PBR cardboard texture along with the 2d image that will effectively define the boundaries of the plane.
Here is what it currently looks like in the Shader:

Using my more familiar 2d parlance, I just want to mask the eges out, so the cardboard texture is alpha'd wherever there isn't a pixel, thereby creating edges (which I can hopefully solidify to give depth).
Additional Thoughts:

I have been pointed toward the Mask Node, but that's relegated to the compositor, not the shader.
Regardless of what tack I take, I realize that I need a lot of subdivisions to support the geometry.
I also realize I could do this manually, but I'd prefer to figure out the proper way to generate whatever assets I might want.

Solution or no, thanks for your attention. Blender is super fun. And frustrating. And then fun again. And then infuriating. Then you feel like a god. Then I take a week off and forget half the terms. Blender is a mixed bag. Also life.
If you use alpha to give transparency I'm not sure you'll be able to give it thickness properly.
What you need to do is use your image as a background, draw a mesh that will have the exact same shape as your star, extrude, unwrap and give it your image as Image Texture.
Or import the shape as svg, make it a mesh, use X &gt; Limited Dissolve to lighten the topology, and same thing, extrude, unwrap and give it the image as Image Texture. In your case the good news is that you won't need to rework the imported SVG.