What is the optimal way of structuring a multiple choice preference evaluation?

Say I have a set of photographs and I want to ascertain the most popular one based on a group of people choosing their favourite.

What is the most optimal way of structuring a survey to derive a confident estimate of the most preferred photo with the smallest sample size.

For example would it be better to do...

Show all photos and ask people to pick their favourite
Show a subset of photos and ask people to pick favourite
Some other structure

Does the optimal structure change if you have more options?