Don't worry....very common mistake....you have saved a thumbnail of the DISign and not the full size image. You need to go to Photobucket (and I'm sure other sites work similarly) and move your mouse around the upper left-hand corner of the image. It will show that you can ZOOM (hi-res or 100% or similar). Open up fill size and then download and save. Now you will have a DISign that you shouldn't have to enlarge....that almost always makes it blurry!
Hope that helps!