Proxy is the full size of the original bitmap.
Proxy is half size in each dimension from the original bitmap.
Proxy is one third the size in each dimension from the original bitmap.
Proxy is one quarter the size in each dimension from the original bitmap.
Proxy is one eighth the size in each dimension from the original bitmap.
{ proxySizeFactor_Full=1, proxySizeFactor_Half=2, proxySizeFactor_Third=3, proxySizeFactor_Quarter=4, proxySizeFactor_Eighth=8, };