Plugin enlarging images making them unsharp

Hello,
The install when smooth. The before and after slider works fine. But it seems the photos weren’t as sharp as the originals. I created a post with the original photos and the before and after slider. The before/after slider is about 10% larger than the original photos making them unsharp. Is there a setting I need to change?

In the linked page, you can see all three images. ( two original files at 100% and before/after image )

Thanks

The page I need help with: [log in to see the link]