Photoshop question, how do you do this?

Question

Hi.. I don't know how to get this effect. Can someone help me please?

Basically, you know how you can make an image black and white, right? That's like using the grey scale.. Now what I wanna do is make an image, but instead of turning it black and white, turn it to some color I specify, so it will be shades of only that color. An example of this is:

http://thenetworkgarden.blogs.com/photos/uncategorized/facebook_logo.jpg

Where Mark Z. (the guy in the photo) basically gave a regular picture of him self, and then turned it a blue-scale. How do you do this?

Turned it into a bluescaled image*

Answer 1

Image: Adjust: Hue and Saturation. Slide the hue slider back and forth for all the colors of the rainbow.

Answer 2

selection the entire image ctrl+a, image > adjustments > black & white, image > adjustments > hue/saturation, click colorize, and play around with the sliders until you get your result