position and PaperPositionMode

There are lots of figure properties, including one i use to specify the size of screen figure output and also .jpg or .eps size. this is helpful if you care about the aspect ratio of your output, which you should.

figurehandle = figure('position', [x1 y1 x2 y2],  'PaperPositionMode', 'auto');

i usually start from the bottom left corner of the screen (x1 = 0, y1 = 0) with units in pixels. The 'auto' makes the printed output (.jpg, .eps, etc.) the same aspect ratio/size.

h1 = figure('position', [0 0 800 1100], 'PaperPositionMode', 'auto');

many other options! figure properties page.