What are the differences between a Black Hole and a Supermassive Black Hole From what I understand, the mass of a black hole should be nearly infinite, how much more massive can something get? 


Is the name to be literally interpreted such that a Supermassive Black Hole just has more mass?
Or rather, is a Supermassive Black Hole just a regular Black Hole with nearly infinite mass that is larger in diameter?
If the difference is in fact a change in diameter, how are the changes in size with the retention of the immense mass reflected in the Supermassive Black Hole's gravitational field?
Stellar mass black holes form from the collapse of massive stars at the end of their lives. You can then find them scattered throughout galaxies, just like you find massive stars. They typically have a mass a few times the mass of the sun.

Supermassive black holes are found at the centers of galaxies. They typically have mass of millions of Suns. 

Recently they have started to discover Intermediate Mass Black Holes which blur the lines between a stellar black hole and supermassive black hole. The typically have a mass in the range 100 to one million solar masses.