Get yourself an image...Here's the duck
Get an icon...Here's the Icon
The image is 300x240. The icon is 32x32.
Now for the math. So the icon will tile even, the background must be divisible by 32... or 320x256.
Because we want the icon to show on each side and top and bottom we add 64 to the width and 64 to the height....making our background 384x320...
Fill color "gold" stroke color "none" stroke width "one".
Top left number will be the icon size 32x32; bottom right numbers will be the width and height minus 32...or 352x288