1. _____________ is a well-known, open source image manipulation package.

  2. Write an algorithm that visits all the pixels (x, y) in a two-dimensional image.

  3. The process of redesigning and reimplementing code without changing its behavior is called ________________.

  4. The brighten and dim image manipulation effects are inverses of one another. Are the flip vertical and flip horizontal effects inverses of one another as well?

  5. Why do you need the modulus operator for the shift effect?