HI Benoit,
The contour graphs can either be matrix or vector for the X,Y but the Z needs to be a matrix based on its values for the corresponding X,Y Pair.
I made a quick example of each method below I hope it shows what I mean.
You can replace individual elements of controls with GIFs too.
I once replaced the pointer in a horizontal point slide with an animated GIF to make a custom progress bar.
In my application I opted for a GIF of two turtles engaging in sexual congress.