Object Style Question

I have to repeatedly insert photos into my document. I want them all to be the same width, with the height proportional (so long as it's less than the length of the page minus margins). So I've created a master page with an X-frame set to 6.5 x 9 (sorry I use inches), and I've created an object style that gives it the border I want, and will resize it proportionally. But I cannot find any option that will fit frame to content. I would prefer to avoid that one extra step every time if possible. Is there a way to add that into my object style that I'm missing?