Is one photograph enough to make something from?

Yes. One photograph and one person is a complete piece — not a degraded version of a group one, and not something waiting for other people to finish it.

The trade is that it puts the whole weight on that single image, which changes what size you can honestly buy.

Nothing here requires other people

A good deal of this product is built around several people contributing, and it is easy to read that as a requirement. It is not. A memory made by one person is finished, and nothing about the result nags at you for contributors who never arrived.

That matters more than it sounds. The single-photograph case is frequently the one that matters most — a picture nobody else in the family has ever seen, because it was in a drawer.

Where the weight lands

With eleven contributions, a weak photograph is carried by the others. With one, there is nothing to carry it.

So the source quality question moves from secondary to central. A soft, small or damaged picture will still work — but it sets a ceiling on the size. There is more on where that ceiling sits in how big can you print an old photograph.

What to write when it is only you

The instinct with one photograph is to write less, because there is only one thing to describe. The opposite is more useful.

Everything the picture does not show has to come from you: who is out of frame, what happened ten minutes later, why that coat. With a group, several people supply those details between them. Alone, you are the only source.

Plain sentences work better than careful ones. He says it was February and he says he was not frightened, which is the part I do not believe does more than a paragraph about what somebody means to you.

The practical answer

If you have one good photograph and the story behind it, you have enough to start. Classic is sized for exactly that case, and it is the smallest piece we make rather than a lesser one.