What rendering services are available to convert URLs to images?

Question

I know some services that encode the description of an image inside on an URL.

For example:

• yuml.me for drawing UML Diagrams:

  or

• www.codecogs.com for rendering LaTeX equations:

  

I really like these services to use them inside my javadoc to illustrate the documentation. On stackoverflow.com it's a bit tricky to encode these URLs, see my request at meta.stackoverflow.com.

Question

Are there any other rendering services that are useful for documenting source code?