pdf in sap businessobjects design studio

hello ,everyone.

I have to use pdf to print my report, so I have set a image as a button to print my report,I was work fine in sap design studio while I was adding an local image into my report ,but when I change the path of image to url,I can see image but I can't print the image.

follow pocture,picture one is what I see,and what I print should like it,but after I print ,I just get picture two.

is the image of url can't print?

waittting for your help!

Jing.