Based on SUPPORT-8159 and detail investigation, currently we didn't have any easy way to provide a custom or direct ImageStreamer, DefaultImageStreamer is hard-coded in info.magnolia.imaging.Imaging.getStreamer(ParameterProviderFactory<E, PT>) and not configurable.
Also DefaultImageStreamer is using Sun provided ImageWriter (and some from twelvemonkeys imageio jpeg) which sometimes didn't satisfy highly demanded customers and it also alter already processed image if we use custom image generator.
Moreover BufferedImage is not a preferred one when customers are using 3rd party library because BufferedImage is a derived value after Magnolia decoded the uploaded image, lost some metadata(s) and used our image decoder which is also not a preferable one. Binary store to and from JCR with BufferedImage in cache would be better.