Yeah, I mean it's so frustrating looking at Jessy Jiggles thread and seeing some of her most recent pics (http://www.curvage.org/forum/imageserver.php?id=187949 for example) with stated resolutions of 2486x3564 and then opening it to find it's been limited to a 750px width max.
This width limit seems to only happen with imageserver hosted images because if you go into imogeneize's thread (www.curvage.org/forum/index.php?topic=6511.0) her pictures don't seem to have the same limitations (at least not that I've noticed) and are hosted on photobucket.
Another example of an image that doesn't appear to be width limited and is hosted on photobucket was submitted by SayHelloToMyLittleFriend (http://i1134.photobucket.com/albums/m619/theraisedlid/lolwut.jpg) with dimensions of 1024x1024. Now, I'm not sure if it's being scaled or not because photobucket images don't seem to give a stated image resolution when not full size, but it is at least wider than 750px for me.