Scale image dynamicaly

Hi,

I followed the steps to insert dynamic images from a url

https://docs.oracle.com/middleware/12211/bip/BIPRD/GUID-58D7E662-146A-44AA-86F9-111E2C6DB3A5.htm#BIPRD2396

the images output get re-sized to the dummy image scale.

Since all images size are different, some of them come out correct but other images looks distorted.

How can I Insert Images with an Element Reference from an XML File without loosing the image real height and width.

Thanks