When my other half mentioned that the leaflet we received from the Labour candidate for York Central looked a little bit "overly white" (paraphrasing), I decided to run the numbers.
The York Unitary Authority's demographics, from the 2011 census show that we have 94.3% "white" people .
We sat down and counted the faces on the leaflet, excluding the candidate themselves. We came to a count of 14 faces, all of which were white.
The chance of picking 14 people at random from a population which is 94.3% white and getting 14 white people is 43.97%. That means that the chance of getting at least one non-white person on the leaflet would've been 56.03%.
Obviously, this is quite close to a toss-up, but bear in mind that these people aren't usually selected for at random. All sorts of biases go into selecting people for photo shoots, from who turns out, to who interacts with the candidate, who the photographer chooses to take photographs of and who is selecting which photos from the shoots end up on the page and their biases towards what will "look good," and what is expected to promote an image of diversity.
Anyways, I don't want to say one way or the other about what this does or does not mean, I just want the data to be available for people.
 : 2011 Census: KS201EW Ethnic group, local authorities in England and Wales (Excel sheet 335Kb) (http://www.ons.gov.uk/ons/publications/re-reference-tables.html?newquery=*&newoffset=0&pageSize=25&edition=tcm%3A77-286262) Accessed: 2015-04-11