Can anyone tell me why the first instance errors while the second doesn't?

SITUATION 1:
imgItem = Image.GetInstance(New Uri("https://www.domain1.com/index_im.cfm?ItemNumberP=AA0220-YE&BM=Y"))

ERROR RETURNED:
System.IO.IOException: https://www.domain1.com/index_im.cfm...AA0220-YE&BM=Y is not a recognized imageformat.
at iTextSharp.text.Image.GetInstance(Uri url) at asf_view_cart.btnCreatePDF_Click(Object sender, EventArgs e)

SITUATION 2:
imgItem = Image.GetInstance(New Uri("http://www.domain1.com/images/item-image.jpg"))

RETURNS WITH NO ERRORS

Any thoughts on how to get the first url to work?

I believe I am using iTextSharp 5.1 (or whatever the latest is)