I just opened a downloaded image of a Hundred Dollar bill into Photoshop, and a government anti counterfeiting web page opened in my browser. WEIRD!
Visit newmoney.gov for the specific regulations.
Here is a summary for authorized color illustrations:
- Illustration must be less that .75 or more than 1.5, in linear dimension, of the currency
- Illustration must be one-sided.
- Destroy or erase anything used in the making of the illustration that contains an image or part of the illustration.