Function image

image(expression: Expression, library: ImageLibrary): string
Generate the image meme of an expression.
Parameters
- expression: Expression
  the expression to generate
- library: ImageLibrary
  the library of named image files
Returns string
a data: URL for the image generated by the expression, according to the language definition in the PS3 handout. See Canvas.toDataURL.

Throws
Error if the image cannot be generated