All of these are NWS. Plan your viewing accordingly.

First, two of my favorite Snarry art pieces with older characters.

When I'm 64 by hill_ from 2007 snarry_games. This thing is priceless no matter your ship. ROFL

When all is Said and Done by jin_fenghuang from 2008 snarry_games. (You can see the individual images here and it does include both older and younger characters.) I actually made an icon for it I liked it so well.

Oh, and how can I forget this gem by tripperfunster: Dumbledore/Slughorn.