That separator syntax should work, yes. Ideally we can escape dashes and 'x' in arguments (e.g. `SomeGenerator200x100xarg--with--dash-test.jpg`), but that's really the icing on the cake. Its quite hacky to store so much metadata in the filename as well, but since we can't generate these images on-demand via HTTP I don't see an easy way around it (can't just treat it as hashed discardable caches). Just had a look how other systems handle that, [paperclip](https://github.com/thoughtbot/paperclip) works around this issue by just allowing style aliases in code - which isn't feasible for us.