OMERO is a Java-based server-client application for microscope image data management, visualization, and analysis. See the OMERO documentation for details. The OMERO.importer client uses Bio-Formats to read image pixels and propagate metadata into the OMERO.server system.
Everything you need comes with the OMERO clients, with no further installation necessary.
The OMERO clients are currently distributed with a static version of Bio-Formats bundled within the jar_0.jar or omero.importer.jar file, and cannot be easily upgraded using the latest loci_tools.jar on this web page. Instead, wait for a new version of the OMERO.importer client.