If your axes limits are fixed, then you could make an image in the same axes, place it outside the axes limits and turn Clipping off so it shows up:
figure();
plot(1:10)
xlim([1 10])
ylim([1 10])
image(gca(),'XData',[-0.5 0.5],'YData',[10 8],'Clipping','off');
On the other hand, if your axes limits may change and you want the image to remain fixed, then it'll be better to make a second axes for the image:
figure();
plot(1:10)
ax2 = axes( ...
'Units','normalized', ...
'Position',[0 0.7 0.1 0.2], ...
'YDir','reverse', ...
'Visible','off');
image(ax2)
