First make sure you're calling imagesc() and not Imagesc() because MATLAB is case sensitive. Look up the help for imagesc. What exactly do you think x and y are that you're passing in? Where is the image array that you're trying to display??? Try this
axes(handles.axes);
imagesc(yourImageArray);
or
imagesc(yourImageArray, 'Parent', handles.axes);
Obviously you already need an axes object on your figure which has the "tag" names "axes" or else that won't work.
