Hi. I am a professional photographer & I travel a lot as my clients are based in different countries. As laptop is quite heavy so I prefer to carry ipad. But the problem is that all my pics get jumbled up & i am unable to show them according a particular theme. So i want something which can help me in organizing my pics. For eg: I want to show my best pics related to nature or wedding etc . then i can easily sort out those particular pics with some keywords etc. Is there any app available which can help me to add tags or keywords etc to my pics?