> In a bad situation you would resolve the image already, but the resolver was only asked whether it has the image stored. 

if we have something in the cache it means it was already stored so we can return true. In terms of cache resolver a cache is kind of a store so I think it is ok to use call `$cache->contains($cacheKey)`  to check whether it was stored or not. 

We can introduce a new key like `resolve` we have now but in this  case the logic would become more complected. The remove logic for example: we would have to synchronously remove `resolve` key and `isStored`.

I'd vote for simple solution for now. we could come back later to review the logic