The poor image quality is related to the resolution of the original image you imported. ie. if you are importing an image 100x100 and resizing to 300x300 you will lose quality. You need to import the image at 300x300 to retain quality.

The browser will automatically add a scrollbar if it is not as large as the stage. Another option is to create a master symbol that contains your flash objects/anim and then apply a scroll bar component along the bottom of the master component.

Hope this helps!