Improve typing of `Image.encode`
Improve typing of `Image.encode`

Instead of returning `any` we're now returning the whole object.

Still from typing perspective, the API is not that
great since we don't have any type relation
between `encode` calls and `encodedWith` property. Maybe we can think about
returning directly from `encode` call
with the returned object having properties
that is supplied in `encode` calls

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