1. A method for enabling searching of images based on image features, the method comprising: using one or more processors to perform steps comprising: programmatically analyzing each image in a collection of images, including determining at least a local feature and a global feature for individual objects that appear in each image of the collection, the local feature of each object corresponding to a visual characteristic of a segment of that object, the global feature of each object corresponding to a visual characteristic of the object as a whole, wherein determining at least a local feature and a global feature for individual objects that appear in each image of the collection comprises, for each object in the image, determining at least a first global feature independently from determining at least a first local feature and by using a global feature extraction module to determine the first global feature from the image; enabling a user to specify a search input; and determining a search result comprising (i) one or more first images that depict objects that individually have a global feature which satisfies a criteria identified from the input, and (ii) one or more second images that depict objects that individually have a local feature that satisfies the criteria.