Images not stretching in forms

This is really odd. I have a liveCycle form with two images. When I base64 encode the images on the client side, the images stretch to fill the box.  (but the client is very slow)  If I base64 encode the image on the server side, the image keeps the proper dimensions and don't stretch.   I want the images to stretch inside the box.   I have "scale image to fit rectangle" set in the form with Livecycle designer

I am using LCDS 2.5 with Livecycle Designer es 2.5

Any help on this would be awesome as this is a big issue at the moment

Thanks