Abstract
Defining ontologies within the multimedia domain still remains a challenging task, due to the complexity of multimedia data and the related associated knowledge. In this paper, we propose: i) a novel multimedia ontology model that combine both low level descriptors and high level semantic concepts; ii) an automatic construction of ontologies using the Flickrweb services, that provide images, tags, Keywords: and sometimes useful annotation describing both the content of an image and personal interesting information. Eventually, we describe an example of automatic ontology construction in a specific domain.