1. A computerized method of image processing to form a collage within a predetermined outline from a plurality of images, the method comprising: processing each image to assign a saliency measure to each pixel, said processing comprising: providing a dissimilarity measure, said dissimilarity measure combining an appearance component and a distance component; finding a first patch of said image; comparing said first patch with other patches at different distances from said first patch using said dissimilarity measure, thereby to obtain a score; applying to each pixel of said first patch said obtained score; continuing said comparing and scoring with additional patches of said image until each pixel obtains a score; from said scored pixels providing for each image a region of interest, by setting an initial boundary that encloses a predetermined set of highest scored pixels, and propagating a curve around said initial boundary in such a way as to minimize length and maximize included saliency; and combining said regions of interest into said collage by: ordering said image regions by importance; placing successive regions within said predetermined outline, said placing being to maximize saliency and compactness and minimize occlusion, thereby to form said collage.