To find the column of an index in a matrix the formula "column = index % width" should be used, not "column = index % height"
If inputFormat.tileCountVertical was equal to 1 then it would not throw an error, but instead result in the first tile of the bitmap always being returned. If inputFormat.tileCountVertical was larger than 1 then Bitmap.createBitmap() would throw an error as it would attempt to go outside the bounds of outputBitmap
ImageRenderTest has been updated to test for 2x3 images so that tileCountVertical != tileCountHorizontal. These tests passed previously because they were equal, so using tileCountVertical produced the same results as tileCountHorizontal