HOW CAN I PLOT GRID AND SHADED IT WITH DIFFERENT SIZE?

I have done in converting the image to binary image with the size of 415x380 using matlab r2018b. And ive done the grid on the image with varies size. How can do loop for 15, 25 and 50 size of the grid? Ive just done it one by one. And also i want that the grid that have more 1's bit pixels to be shaded in white. What function should i use? You can refer to Map maze and what i should change. I'm doing this for a path planning. Thank you.