Why water mark the title screen images?

Many games on the website feature images of the title screen, which is really useful for creating Wii U injects as they are preferable for creating image files for the injects.

The problem is, the images feature "vimm.net" watermarks and are not proper images (right-clicking on them has no save as or open in new tab). I don't feel like it's necessary for these title screen images to be watermarked and not be proper images.

If someone can explain why they are like this, that would be appreciated. I do hope this changes at some point.