Take a self portrait with Photobooth.

Open your image in Pixlr

• Filter
  • Pixelate
• Adjustment
  • Desaturate
  • levels
  • Posterize
  • Hue/Saturation
  • Colorize
• Crop
• Use the Text tool to type pixel dimensions and RGB Values.

To find color values, save and open your image in:

http://www.csfieldguide.org.nz/releases/1.9.9/_static/interactives/dr/pixel-values/index.html

To take a screen shot use keyboard shortcut “Command + Shift +4”