Does the white_chocolate tag also fall under the chocolate tag? If it does there isn't an issue, but if it didn't (visual difference, etc) then you couldn't implicate chocolate_heart to chocolate since they could be also made of white chocolate.
The only images with white chocolate hearts so far are already tagged chocolate anyway, so it seems we're not making a distinction as it is. I think the chocolate tag is supposed to be general and not specify any distinct type of chocolate anyway.
It's worth mentioning that white chocolate is not technically chocolate; just cocoa butter. However, since white chocolate is considered to be chocolate by the majority of the population, I'm not against including it as a subset of the chocolate tag.
