Data visualization takes an important place in image processing. Data can be a simple unique 2D image or a more complex with multidimensional aspects: 3D in space, timeslapse, multiple channels.
Therefore, the visualization strategy will depend on the data complexity and a range of tools external to scikit-image can be used for this purpose. Historically, scikit-image provided viewer tools but powerful packages are now available and must be preferred.
Matplotlib is a library able to generate static plots, which includes image visualization.