I've tried everything and I still don't understand how in the world this is supposed to work. I experimented with the picture of the Austin, and found I couldn't make it be lower than 129.19 KB without it being 720x405. I don't know what I'm doing wrong, but there is just no way I'm able to make the filesize smaller but keep the dimensions the same.

EDIT: I did find one way. By resizing the picture to 500x281, then saving it, then resizing it back to 720x405, with the resulting filesize lowered to 23.9 KB....but with a (very minor) loss of picture quality.

EDIT II: I'm now fooling around with screenshots of the cars from Darkman. Oddly, when in their original size of 864x486, their filesize is only 31.40 KB...and I used Sonic CinePlayer to take them just as I did with Island of Terror and the others. What gives? Does it have something to do with the quality of the DVD? Because the visual quality of the Darkman DVD is way better than that of Island of Terror's....