In your GUI tag the axes you want to be used
Wherever you want to execute the code to show the results do this
Setting the axes to the current one might not work so it's better to give the handle for the axes to the function that plots/draws the image.
Example, if you want to plot on your GUI axes do this:
Last step: In the GUIDE layout click on the background of the GUI with your mouse right button, choose GUI Options, now change the command line accessibility to ON, now my solution of tagging the axes works just fine.
It works while the GUI is open and the axes tagged so you can do that plot even in the command line or any m-file.