Check out the differencesÂ between a standard release and an IMAX release for the Guardians of the Galaxy movie.
Someone apparently went and uploaded a batch of images on imjur (via reddit) revealing how IMAX shows further footage.
While James Gunn didn't use IMAX cameras, he did plan on the larger screens (and 3D) for IMAX.
Gunn stated the following back in June:
As an EXTRA benefit for those who see the film in IMAX 3D, we will be changing aspect ratios throughout the film in a way that makes the experience even fuller and more encompassing. I've personally chosen all the places where the changes occur and, again, I love how it's coming along. The changing aspect ratios in this case are actually a part of the storytelling.
Regarding which version of the movie the Blu-Ray that gets released on Tuesday will feature, the standard version (left side) may be the regular Blu-Ray, with the IMAX version the 3D Blu-Ray. However, don't quote me on that.