Would a cheetah.png file be better?
Is there a rule against placing the file in the examples folder?
No rule. The only concern is the size used by the examples. Lazarus distribution is quite big already.
One choice would be to use an existing image under Lazarus dir using a relative path. It would work always except if the example project is copied somewhere.
Another issue with examples are missing ReadMe.txt files. The Tools -> Example Projects ... window shows a project's ReadMe file automatically if it exists, but most projects don't have it.
Yet another issue are poor descriptions in Lazarus packages. They are shown for example in Install/Uninstall packages window and would be useful.
Patches are welcome for both project ReadMe files and package descriptions, and for other improvements, too.