ensuring that the images you use are representative does not necessarily entail examining every single relevant image however .almost all content analyses rely on some sort of sampling procedure . this is because most content analyses work with large data sets ;it should be both representative and significant . there are a number of sampling strategies described in krippendorf . they include:
1- random . number each image from 1 onwards , and use a random number table to pick out a significant number of images to analyse .
2- stratified . sample from subgroups that already exist in the data set , choosing your image from within each subgroup and again using a clear samping strategy .
3- systematic . select every third or tenth or nth images . be careful that the interval you are using between images does not coincide with a cyclical pattern in your source material , otherwise your sample will not be representative.
4- cluster. choose groups at random and sample from them only