This is the right place for Ren'Py help. Please ask one question per thread, use a descriptive subject like 'NotFound error in option.rpy' , and include all the relevant information - especially any relevant code and traceback messages. Use the code tag to format scripts.
There are three pictures (tree, cat, mountain for example); and every time you open the game it can be any one of these. You could open and see the cat picture, and the next time you close the game it may be the cat again, or show either the tree or the mountain picture.
Sorry if it's confusing, english isn't my native language