(Not because they actually do want it but don't have the resources. Not because it is hard for an external body to do but might be easier for the WMF to do. No, those aren't possible at all.)
Well, given that an image filter is a technically easy proposition, no, its not because of lack of resources that the wiki's haven't implemented one. If the community had wanted one it would have been developed and ready to go years ago.
The WMF foundation has no business doing X if the community already has the ability do X. They were created to do what we can not, manage servers and legal.
We have already seen top down control fail with Nupedia and Citizendium.
Jorgenev