Over 30 years ago, the elders were always trying to involve children in feeling special about being a witness. For the CO i'm guessing, children were encouraged to draw a paradise picture. At the end of the meeting they came up to the stage and stood with their pictures. Parents took photos.
This was at a time when several wives started having babies in spite of the "it's too close to the end" and "this world is too bad to have children" spin. Have to make sure they stay in the fold you know.