That is one of the quirks of using different styles.
Since you can have different color schemes you can also have different smileys with different background colors per say.
In the style editor it is called Graemlin Images
Under Name, Images & Wrapper
So say you are using the gold style.
But you upload a smiley to actually the stock folder.
You will need to upload it again to the folder you use for the gold style.
So you could end up with duplicate identical images on your site.
So with that said your missing smiley is probably in the specified folder for the style it appears but not in the gold style folder specified in your style.
