Change axis gridline line without affecting ticks and labels

The following codes produce a sponge-cake shaped object:

img = zeros(100,100)+5;
img(1,:)=0;
img(end,:)=0;
img(:,1)=0;
img(:,end)=0;

surf(img)
shading interp
axis tight

How can I:

1. suppress z-axis 2. suppress x- and y-axis grid line 3. print the ticks on the side surface, tick color = white 4. re-scale the x- and y-axis labels by /10.