No, that's more something like
sf::Image::Copy(const sf::Image& Source, const sf::IntRect Area, ...)
This one is not very hard to implement, you can already do it by copying pixels in a loop. The main reason for adding it to SFML is to make it faster using internal data rather that GetPixel / SetPixel.
What you're talking about is render-to-image, which is also in the roadmap. This feature is more complex and will take longer to implement.