Is this possible? I am very new to particle systems and materials.
When I last tried to do something like that, it only worked with vertex colors.
You would have to bake your texture colors to the mesh vertices!
I chose spawn particle from mesh. There is an inherit color option. So if your particle material reads the alpha channel of the particle color, particles will still spawn from the whole mesh, but be visible only where the emitting vertex has opacity.
It’s been a while, but I hope this helps!