1. A computer-implemented method for classification of images of an image stream, the method comprising: receiving an image stream of unclassified images; receiving user input about classification of a subset of unclassified images of the image stream, wherein said receiving user input comprises: receiving indirect input of user interest in an image during review of the image stream by said user; and automatically generating user-based indications about classification of images according to the indirect input of user interest; identifying attributes of the received unclassified images; and adapting an initial classification algorithm to classify images to groups, based on the user-based indications and based on attributes of at least a subset of the received image stream of unclassified images.