That's right.
It would be handy if someone made one, since it's not hard to distinguish .png's of .gif's. When you open a PNG file in Notepad, you'll see it begins with:
code:
‰PNG
By looking for that, a developer can determine if the .dat is a PNG.
GIF's always start with:
code:
GIF
so that's another way to check the type of the image.
If any developer is good enough to make a small program which can save.dat's with their right image format in another folder, it would be really helpful!
/ 
