please can someone help me to understand this code

If pos(9)=16 Then
            j=9
            pos(j)=pos(i)
            pos(i)=16
            Imgstr(i)=NumberFormat(pos(i),2,0) & imw & ".png"
            Img(i).Bitmap=LoadBitmap(File.DirAssets,Imgstr(i))
            Imgstr(j)=NumberFormat(pos(j),2,0) & imw & ".png"
            Img(j).Bitmap=LoadBitmap(File.DirAssets,Imgstr(j))
            moves=moves+1
        End If