Blue = Searched Pixel
Black and Green borders = PixelSearch Area
If PixelSearch returns x and y as a blue pixel, you can pixelsearch 2 more rectangles to find the rest of the blue pixels. The first rectangle would be (top,left,bottom,right) = (y+1,originalLeft,originalBottom,x). With original I mean the same parameters as used in the previous pixelsearch. 2nd rectangle: (y,x+1,originalBottom,originalRight). If you find another blue pixel in these pixelsearchs, you must call this procedure recursively. In that way you would find all blue pixels and could return them as an array.
Or you use the FastFind.au3 with FFNearestPixel and FFAddExcluded Area doing more or less the same thing