Abstract: Region-based approach has become a popular research trend in the field of multimedia database retrieval. In this paper, we present the Region Frequency and Inverse Picture Frequency (RF*IPF) weighting, a measure developed to unify region-based multimedia retrieval systems with text-based information retrieval systems. The weighting mea-sure gives the highest weight to regions that occur often in a small number of images in the database. These regions are considered discriminators. With this weighting measure, we can blend image retrieval techniques with TF*IDF-based text retrieval techniques for large-scale Web applications. The RF*IPF weighting has been implemented as a part of our experimental SIMPLIcity image retrieval system and tested on a database of about 200,000 general-purpose images. Experiments have shown that this technique is effective in discriminating images of different semantics. Additionally, the overall similarity approach enables a simple querying interface for multimedia information retrieval systems.