HEY YOU. Welcome!
I'm new around here too, so don't feel lonely. ;3;
And about the pictures, people just get some off the web and make it look nice through editing. They take out the background so there's just the character on the picture. As for the signatures, I'm not quite sure. I made my own.. and it's quite.. simple.
anways, Welcome to the forums and hope you have a nice stay. ;u;