And it is correct that it doesn't work. The token you would get with your comparison would be the filename without extension.
has two tokens if the seperator is ".": "example" and "png"
Looking for the first token (index = 1) would only be true if you'd compare to "example"
Looking for the second token (index = 2) would only be true if you'd compare with "png" (and not ".png", the dot is the seperator of your tokenized list)
This should work:
+ System: GetToken(File.CurFile, 2, ".") Equal to "png"
It only works with normal filenames! For example, if the filename is "somepicture.jpg.png" then you would need to compare against the third token.
A better working way for you is
+ System: GetToken(File.CurFile, NumTokens(File.CurFile, "."), ".") Equal to "png"
This will always look at the last extension of a file's name.