The documentation states, that "tk2dSpriteCollectionData.GetSpriteIdByName" "Returns: Unique Sprite Id. 0 if sprite isn't found."
I'm confused why this version exists. There might be an image with the index 0, so you won't be able to tell of it's empty or actually there, both return 0.
I know there's the overloaded version where you can define a default value for checking.
Wouldn't it be better to leave the index of 0 out of the sprite indexes?