Hack for changing image width in Canvas Portfolio?

Anyone know of a way to adjust the code so that I can adjust the width of the large photo displayed on the Canvas theme Portfolio Post page? This is the large image displayed after you link from the Portfolio thumbnail page. Its default width is 500px wide with no alternate settings adjustment option anywhere. With a 1100px wide gallery page I’d like to be able to increase the large display to about 700-800px.
Thanks