If you’re familiar with OpenCV from the C++ side, Julia’s storage is actually more similar than Python’s: we don’t use an array dimension to encode color because we, like OpenCV/C++, have real color types. It’s just the OpenCV Python wrapper that encodes color via an extra array dimension.
@vladimir, I agree the OpenCV package needs work. Since you care a lot about that, obviously it would be great if you’d help out. Alternatively, echoing @gbaraldi’s comment, what is JuliaImages missing? I know OpenCV has a lot of stuff JuliaImages doesn’t have, but the converse is also true: we’re actually much better for certain tasks than OpenCV. Consequently, a specific list of requirements would be more useful than “necessary for professional image processing.”
If you’re worried about performance, don’t be: we’re only now starting to put together benchmarks, but the preliminary results are quite encouraging 
. Do report any issues you discover, as most bottlenecks are fixable.