Backend Thumbnail issues

We are having problems with the backend thumbnail creator. I am using firefox, the client is using IE8. The Create photo manually sometimes loads right and the photo is on the left side and I can use the box to select what I want. Other times the photo loads in the center and when I select it it looks like the added screen shot. I think this is because the photo is a rather large XXXX by XXXX and not 640 by 480. Is there a way to fix this as I cannot control what size photos they will be taking for the houses??