Ashtangi guy
You will need all the photos only on FI: one full length business attire, 6 passport size business attire (they must be the same -the full length and passport size, I mean) and some casual ones. Usually they need 2 casual photos, but take some more with you so they could choose. For example they took 3 from me. They will also need colored copies of your passport, copy of your highest educational certificate and prove of current emplyment, if you are currently employed. It can be anything-certifacte, pay slip, whatever.These are the documents you will need if you reach FI. So it is better to be prepared. Otherwise you can always send whatever is missing afterwards, but if you give them everything during FI it will speed up the process.
Hope it helps. Good luck