Trouble with Easy Watermark Plugin

Not sure if you can help. I had this working, but now it doesn't. I am using Easy Digital Downloads and the Easy Watermark free plugin. I have the watermark set to go on all medium and large images but not on the full size since those are the ones I'm selling via the EDD. I had the watermark showing correctly so that after clicking on a non-watermarked thumbnail in the Gallery of Downloads, you would go to the separate Digital Download page and the image was watermarked. I started uploading lots of images. I just applied the watermark to four images by checking boxes in the Media Library and applying the watermark. Now, however in the Gallery, whenI click on a thumbnail, it goes to a medium-sized image that has no watermark. I cannot figure out what setting to change. In the dashboard, Settings/Media, I altered the size of the thumbnails and allowed for sizes that I wanted for medium and large. In the Easy Watermark settings, I have it set to go on medium and large. Can you make any suggestions? The site is not live, but Mahesh has login info if you need it. Or I can provide new one. Thanks.