There's not really a benefit to seeing a realtime stream of Twitter photos. In fact, if you were to show me photos that were timedelayed by minutes, hours, or even days, how would I even know the difference? Realtime is effective to get a grasp of what's going on now, but there's no way to discern that from a raw real-time feed. As an example, you don't get the "pulse" of Twitter by reading the firehose, but through the trending hashtags/terms, which are pre-processed and clustered.
In other words, I think there's a lot you could do by clustering/filtering around several kinds of facets. For example, show just pics from accounts with more than x number of followers as a proxy for "quality". That'd be a start and a relatively easy one to implement.