The development of increasingly complex multimedia applications calls for new methodologies for the organization and retrieval of still images and video sequences. Query and retrieval methods based on image content promise good results, are currently widely investigated and, to some extent, already commercially available. Yet a large number of issues remain unsolved. In this paper we describe some results of a study on similarity evaluation in image retrieval using color, object orientation and relative position as content features. A simple prototype system is also introduced that computes the feature descriptors and performs queries. Although not trivial, the features extraction process is completely automated and requires no user intervention. The system is admittedly not a general purpose tool, but is oriented to thematic image repositories where the semantics of stored images are limited to a specific domain.