i don't quite understand your question and your program, but i understand this :
these is a 10 pixel x 10 pixel sized red square in a picture, we need to find it and draw a circle around it.
well we can solved like this, we need an 10x10 array which will hold the color values... also we need another 2d array which is for the circle, for example a 15x15, we need to fill this array only for once at the beginning.
we start to get every 10x10 from the picture and check if all of the values are RED. then when we found red square we put the circle-array over the red square...
that is the algorithm i found...
i hope i understand correctly.