Since Counter-Strike: Source does not support printing text in custom locations.
You will be able to display an image, watermark, image of text, or so on with this plugin.
It is fairly straight forward. Edit customhud.kv to your sprites and adjust the yaw (left and right position), pitch (up and down position), and distance (how far away the sprite is from the client viewing it) to the needs of your sprite.
You can add as many sprites as you want and position them anywhere.
The size of my example sprite is 128x128.