Don’t watermark below certain size?

I have my site running with East Watermark and had no issues until I decided to use the image watermark instead of the text watermark.

Is there a way to set up the scaling so it works based on image size, or better yet not watermark small images? I have it set to watermark only the large and full size images, yet for some reason it still watermarks an image that’s only 672×292.

Having said that if I open my site in internet explorer it’s showing the 672×292 images without a watermark yet if I open it in chrome it shows them with a watermark that covers say 40% of the image.