Pasting imaging from clipboard is released, but is only implemented on the new (experimental) RTE editor, which has to be optionally enabled in Settings.

https://github.com/vector-im/riot-web/issues/1855 is the issue tracking indexing file uploads. Patches welcome if anyone wants to add this into synapse; it'd be pretty easy and fun (although obviously wouldn't work with encrypted rooms). https://github.com/matrix-org/synapse/blob/master/synapse/re... would be the place to index the file and chuck its contents into the existing full text search tables via something like https://github.com/matrix-org/synapse/blob/master/synapse/st....

My point is that Riot is FOSS, and if folks feel features are missing, please help us implement them O:-)