Is it possible to limit the allowed size for normal users (with permissions), e.g. 256x256?

Currently not, but it's a good idea.

@AmauryCarrade Any news? ^^

The size limit would be a great feature. On top of that, a custom size would be absolutely amazing. I don't know if this is exactly possible due to this really being an API for MapManager, but if it is, it would really complete the plugin.

Is this already implemented? :)