A wedding gift from the whole family
Two families are meeting who mostly have not met. A piece made from both sides is one of the few gifts that says something the day itself does not.
Collect from both sides. A wedding is two families meeting who mostly have not met, and a piece built from both is one of the few gifts that says something the day itself does not — that these are now one set of people.
Ask each side for photographs of their own person growing up, not of the couple. The couple have those.
The ask that works
One photograph of the bride as a child from her side, one of the groom from his, and a line each. Then the same from as many relatives as will answer.
What comes back is a piece nobody at the wedding has seen, because neither family has the other's album. That is the whole reason it lands — every other gift on the table is something one side could have produced alone.
Route it through the two mothers
This is the practical bit. Do not try to collect from both families yourself unless you are marrying into one of them, and even then it is awkward.
Ask one person on each side — in practice usually the mothers — to gather their own family's contributions and send them on. Two people chasing five each works; one person chasing ten across a family they half know does not.
Timing around a wedding
Everything in the six weeks before a wedding is competing with the wedding. Ask early, or ask afterwards.
Afterwards is genuinely good and underused: the month after the wedding is quiet, everyone is still in touch, and a piece that arrives in week three lands when the couple have run out of things to open.
Keep the date off it
A wedding gift carrying the date is a wedding gift. One carrying two families and what they said is still worth having on a wall at the tenth anniversary, when the date has stopped being the interesting part.
The test is the same as for any occasion piece: does it still make sense a year later.
Where a whole family is putting its name to one piece, Signature is the usual size. The mechanics of chasing two families at once are the same as chasing one, and are covered in how to get relatives to actually send you the photos.