Couldn't you just specify w and h in the drawpic command, or use the -s switch, to adjust the picture to the size you need? Of course, looks sloppy when making the pictures bigger, and probably is more costly on resources than just doing a manual resize of the source images yourself before using....
Also... why didn't any of us think to use -c in the drawpic? Probably wouldn't make too much of a difference with the way it runs anyway, but you may as well cache them since you'll be reusing them again and again until the clock is closed.
Also, @pball: Analog clock has already been done by BlueThen, years ago lol. It was the script that I used for reference to learn how to draw lines in any specific angle ^_^
Also, maybe someone could include elements of my Higher-Resolution Timestamp snippet to give the time which includes hundredths of a second, for those who really need to know the EXACT TIME lol. Wonder how laggy it would be?