Did you double check so the cfg code was called the exact same as the image file, as well as the format?
If you're not sure how to check if they're png or jpg, just click on them and depending on your operating system, it may show you in the folder.
Otherwise, right click on an image, click on properties and check which format it says.
Speaking of Operating systems, which one do you use?
Sometimes the images/cfg can be saved in different formats without noticing.
The eye may be png and tail jpg, for example.
In my experience, this should not effect the preset in any strange way.