How can I plot intensity values given pixel positions?

Hi!

I have a matrix with intensity values that are the pixels of an image 318x1000. I have to locate these pixels in fixed positions.

For example, if the first row is

I=[96 99 96 100 99 98]

x1=[3.38 3.41 3.45 3.49 3.535 3.5738]

y1=[1 1 1 1 1 1]

the second one

x2=[4.35 4.46 4.47 4.49 4.60 4.66]

y2=[2 2 2 2 2 2]

how can I plot them in the same image? imagesc just define the I(1,1) and I(318,1000) pixel position.