How could we define and perform Image Classification based on Semantic Web technologies ? What about ontologies as a mean to express image classification ? Are they of use in the image classification context ?
When embedding an image in a HTML 5 document you can use Microdata or RDFa to give meta-information e.g. about image classification regarding to an ontology of your choice (if you don't find an existing e.g. at Schema.org one fitting your needs, you can create one on your own for example with Protegé, provide it via a www-accessible server and use that's URL as base for your itemtype)
A suitable element to en-capsule your meta data could be the -tag enriched with itemscope attribute. Point it to the ontology of your choice via itemtype attribute and describe further meta-information in (possibly hidden) contained elements inside the container element.
We have a system for attaching semantic (RDF) markup to images available for use right now. It is called ImageSnippets. (http://www.imagesnippets.com) Feel free to play with it and contact us (myself and/or Margaret Warren) if you have any further questions. ImageSnippets uses the LIO ontology that Andre refers to, though it is now slightly modified from the version described in that paper.