Figures play an important role in the process of understanding a scholarly publication, providing overviews of large amounts of data or ideas that are difficult to present using only the text. This work presents a system allowing to describe and to search for scientific figures in the High Energy Physics (HEP) domain. It proposes an application HEP Figures Ontology (HFO), based on existing ontologies, for the annotation of scientific figures in a semantic triplestore. Finally, this work studies the searching functionalities provided by triplestores based on the HFO model, and compares them with traditional digital library systems.