messing with iframe height

i'm so confused! i have an iframe with picture content on my index page. my index page scrolls down and has a div tag on it since it's my blog. now i want the iframe to stop when the div stops, so it doesn't show all of the picture content, it's height is whatever the div's is. but since it's my blog, my div tag will change height and i'm not going to measure it after every entry to plug into my iframe height.

making the iframe's height:100% only makes it as high as the window, but once you scroll... there's nothing. is there any way that you can make the iframe height to automatically adjust to however far you scroll?