How do I make part of a texture transparent? How to make some part of the texture transparent? I'm using the image below:

Is it possible to just use 1 image, by making that the texture won't render ONLY the black color? 
Is it possible to use 2 images (1 for texture, 1 for mask)?
I know that it can be done with transparent PNG. Just curious about the other method, which allows me to use JPEG. Most of the tutorial I found so far is only about making texture half-visible, which is not what I seek.
You can connect it like this:

NOTE - your image has good black and white cutoffs, so you probably don't need the ColorRamp for the alpha, but in case there's more gradient, that's how you solve it. Also, pay attention to the blend modes I've highlighted. You can pick anything to your liking, just not opaque.