Create pop-art the easy way!
You can start with any image you like..  If you wish use the image below.

(right click over the image and save it - then open in Photoshop Elements)

If you are using your own photo you will need to delete the background by using the magic eraser tool and then the eraser.  Although care and time should be taken. 

This image has a white background so it will be easy to delete the background

(the grey checker board shows the deleted and transparent background)

Lets start:  Filter -> Adjustments -> Threshold

move the slider left or right, until you get satisfying picture...

Now duplicate the image 3 time.  Rename each on as 1, 2, 3 and 4

Now change the foreground colour to something bright.  Select the fill tool
Change parts of the image to different colours

Do this for the other 3 layers as well.

Tip: Hide 3 layers and work on the other to make life easier.

Increase the size of the canvas so that all 4 can be placed next to each other:

Image > Resize > Canvas Size ...

Change the measurement to percent and the width and height to 100%

You will then be able to select each layer and move the images so that

they are side by side

Here is just a start: