i have tried on the following setups.
windows 8, using google chrome and opera web browsers, screen size is (1600 x 900)
mac os x 10.9.2, using safari, firefox, and google chrome, screen size is(1280 x 800)
I wasn't able to reproduce the error either in your site or in the demo and using the same screen sizes and the same image selection (+40 images). I think that this issue could be related to the image reader of the uploader and sadly to test that I will need to use the same files that you want to upload.
In the case that the system works with the stock photos then we can move forward to the image reader and see why some of your photos are causing the issue.
so i have let the page load (including images) before i try to scroll, it creates the bug when i try to scroll down before the loading is finished, try uploading 50 to 100+ images at once it will lock up the script
That could be an issue. The reader uses JavaScript and I never test it with a lot of large images. As you may notice than can really stress the computer and maybe the script execution is halted. But I think that the issue is the images, maybe the reader just dribbles around.
The nature of the issue is most likely to be too much computing for the javascript and javascript runs in your computer. It will need a little more testing to identify a workaround.
Chevereto is using Javascript to display the image thumbnails of each image in the upload window. This results in that each image is fully loaded into the browsers memory. Because of security reasons the script halts when too much memory is being used too fast or just runs out.