How to use function if
I´m trying to use the function "if". I have read in other answer that is necessary to use the function if not exists (__,__) but I did not know how to use it.
I do not know almost anything regarding programming language but I need to understand how it works this function.
What I am trying to do is that the system select an image and if exists the system follow one path and if it does not follow another different.
I would be grateful if anybody can help me with this.
Thanks a lot in advanced