1. If photos have a hashtag, display it alongside an image. Text is the underestimated medium of non-personal image interpretation. Especially, when the data rate is so high, there needs to be some more precise clue about what the images are actually trying to convey.
2. Aggregate photos with similar intent. Group them into a box or color code their borders. Many tweets have GPS tags. Use them to provide a map interface to either filter some or just add a tag indicating the place of origin.
3. Most people who can only read 2-3 languages, and tweets in other languages will be treated as noise, no matter how relevant. The only alternative is combine them with a similar tweet in a language the user can understand.
4. Is there any reason photos change randomly across cells, and not in any order (as compared to say raster scanning the table and replacing photos)? Personally think that changing photos in some order is less painful on the eyes. I get the feeling that I am missing out an a lot of content because of this. Maybe replace only one section of the table at at time?
Good luck!