how to change the plot background?

I want to show the background of the plot above like the plot below.

This is the code for each.

Answer 1

[Constantino Carlos Reyes-Aldasoro]

Most probably the first figure you are showing is and RGB (type "whos" and look for the dimensions it should be rows x columns x 3) and that is why it is not appearing with the colour map. The second image is just intensity based (rows x columns). If you check that then we can follow and display as you want.