Manipulate[
  If[r==1,S=Image[Inverse[RandomReal[1,{Round[P[[1]]],Round[P[[1]]]}]],ImageSize->{500,500}]];
  If[r==2,S=ListDensityPlot[Inverse[RandomReal[1,{Round[P[[1]]],Round[P[[1]]]}]],Frame->False,Axes->False,ImageSize->{500,500}]];
  If[r==3,S=ListDensityPlot[Inverse[RandomReal[1,{Round[P[[1]]],Round[P[[1]]]}]],Frame->False,Axes->False,ColorFunction->Hue,ImageSize->{500,500}]];
  S,{{r,2,"RasterColorType:"},{1->"BlackandWhite",2->"2Color",3->"3Hue"}},
  Control[{{P,{10,10}},{1,1},{500,500},ImageSize->{350,100}}]
]