Documentation is very clear about this point: http://www.jboss.org/file-access/default/members/jbossrichfaces/freezone/docs/devguide/en/html/mediaOutput.html.
"value": data value calculated at render time and stored in URI (also as part of cache Key ), at generation time passed to send method. Can be used for update cache at change of generating conditions, and for creating beans as "Lightweight" pattern components (request scope). IMPORTANT: Since serialized data stored in URI, avoid using big objects.
There's a certain limit for length of URLs and data is encoded in URL, that's why this doesn't work. And the bug you are referring too was in fact fixed; the problem was in incorrect flushing code and not in large data.
Is there any way to create images dynamically from database if image is stored as blob or byte array?
Sure. Make "value" attribute a key for data and then read blob data from DB using that key and transfer it just into OutputStream passed as method argument.
Thanks, I'll try to do this in the evening.