1. A method of classifying a scene depicted in an digital image, the method comprising: receiving an input image in a first scene classifier; forming a first plurality of image features from the input image; processing the first plurality of image features in the first scene classifier using a set of first sub-classifiers, each first sub-classifier determining first classification data for one of the first plurality of image features; classifying the image, in a first final classifier of the first scene classifier, as an indoor scene or an outdoor scene based on the first classification data determined by the set of first sub-classifiers; if the image is classified as an outdoor scene, forming a second plurality of image features from the input image in a second scene classifier; processing each of the second plurality of image features in the second scene classifier using a set of second sub-classifiers, each second sub-classifier determining second classification data for one of the second plurality of image features; and classifying the image, in a second final classifier of the second scene classifier, as an outdoor urban scene or an outdoor natural scene based on the second classification data determined by the set of second sub-classifiers.