depends on how comfortable i feel with that gager so could take days or weeks. no one's ever asked to see what i look like albeit i have messaged a gager pestering him or her to show me a pic of himself or herself.
Like everything in life it is up to you - Oddly enough most people I talk to would have profile pics and post selfies I only recall one person coming to a decision to send me a pic and that was after a couple of conversations.
I would be very hesitant to send pictures or any personal information to anyone on here because you don't really know who it might be or what they might do with it. Only you can determine your required trust level. I only suggest you set it to very, very high.