When I created the 1st and only Reunion booklet for our family reunion, getting copies of older pictures became a chore. I went to kinko's and copied each one, I received so I would have a record on paper. Anytime I am around the younger generation I do my best to get a family group picture and keep that on a KODAK CD and photo paper shot's. It's easier to show these and not be concerned with losing them. In order to get family charts I sent request to a teenage member of that family unit. They became interested and I got great information. Now I am updating this information. I suggest when trying to get families interested, target the young ones with a letter sent to them. I also purposely 'make little mistakes' to see if anyone is paying attention. The family chart software I have allows me to scan a picture and insert it next to the name in the family chart. This way if I have to send off for info I get better pictures and names and faces will mean something to all. Try doing this with letter's sent out to members about family events. For each letter you send out, include a family chart for the head of that household. Everybody likes to see their name in print, and want the best picture possible to be seen. Complete ancestry charts will only be in a reunion booklet. But you know, I am getting pictures I have been begging for, to go in the next booklet.
Sometimes you just have to a little try 'trickery' to get results.