We talked with photojournalist Ed Kashi about visual storytelling, advocacy journalism, and his photo series on Trans Amadi Slaughter, an abattoir on the Niger Delta. Q: At the Digest, we’ve talked about whether a series of photos needs to work the same way as a print story: a character, a conflict, rising tension, climax, resolution. Do you think a photo montage or a slide show functions by the same rules? Or does it have a different narrative structure? A: I think it can go both ways. The...