starting with oriental-bay.jpg, size (450, 325)
resizing to (16, 12)
             NEAREST:             0.000022
            BILINEAR:             0.000112
             BICUBIC:             0.000192
        AREA_AVERAGE:             0.001558
           ANTIALIAS:             0.009321

stretching to (16, 12)
             NEAREST:             0.002765
            BILINEAR:             0.003934
             BICUBIC:             0.006127
           ANTIALIAS:             0.008903


on VIA C3 1 Ghz:

resizing 1000 times, (450, 325) -> (16, 12) ...
Area average took                   14.217369 seconds.
nearest neighbour stretch took      19.195978 seconds.

on Athlon XP 2800+:

resizing 1000 times (450, 325) -> (16, 12) ...
Area average took                1.611024 seconds.
nearest neighbour stretch took   2.746200 seconds.

Click the image below to cycle through unscaled, area averaged and nearest-neighbour-stetched images.

Original	Area Average
Antialias - resize	Bicubic - resize
Bilinear - resize	Nearest neighbour - resize
Antialias - stretch	Bicubic - stetch
Bilinear - stretch	Nearest neighbour - stretch