How can I generate an image using buildroot with opencv2 in it?
In "Target Packages->Libraries->Graphics->opencv2.4" says that python_opencv depends on numpy, which isn't available.
An self made app(which is in the built image as well) uses python3.6 and opencv2.
Buildroot Version: 2017.08-rc3
Back when opencv was introduced in Buildroot, there was indeed no numpy package, so support for doing OpenCV in Python could not be added, hence this comment. But since then, a python-numpy package was added, and it is even used in the opencv3 package to provide Python support.
So, the opencv package simply needs to be updated to leverage the python-numpy package to provide Python support.
As a side note: why are you using 2017.08-rc3 ? It is a release candidate, not even a final release. And why this version ? Why not using the LTS version 2018.02.x, which we maintain during one year with security updates and bug fixes ?