keyword hierarchy and search
Keywords can already be arranged in a hierarchy: Countries --> USA --> California --> San Francisco
According to this hierarchy, it implies that any picture with the keyword California also belongs in the more general keyword USA. However, the search doesn't work that way. This is fine if I create the hierarchy of keywords first, and then add the keywords, but if I have an existing photo already tagged with 'California', and NOT tagged with 'USA', then it would not be found when I search for USA.
The search could be made more powerful by allowing the use of the hierarchy of keywords.