In this paper, we describe a system to perform Document Image Retrieval in Digital Libraries. The system allows users to retrieve digitized pages on the basis of layout similarities and to make textual searches on the documents without relying on OCR. The system is discussed in the context of recent applications of document image retrieval in the field of Digital Libraries. We present the different techniques in a single framework in which the emphasis is put on the representation level at which the similarity between the query and the indexed documents is computed. We also report the results of some recent experiments on the use of layout-based document image retrieval.