The same photo mug for the Christmas gifting season, with the December ordering deadline on the page.
The same photo mug for a new arrival, a nursery or a first-year keepsake.
The same photo mug for anniversaries and milestone years together.
One mug per place setting, with the couple's photograph on one side and the guest's name on the other. At volume pricing it costs less per head than most bought favours and nobody leaves it on the table.
Two porcelain mugs from a photograph taken on the day, given at the first anniversary rather than at the wedding, when the couple have stopped receiving things and started using them.
Bridesmaids, ushers, the person who did the flowers. A mug with a photo of that person with the couple is specific enough to read as thought rather than obligation.
The magic mug, which hides the photograph until a hot drink goes in, is the version that gets passed round. Cheap enough to buy several, personal enough to be worth opening.