I been in this specific business for 15 years working with photo galleries and clients who want to protect their photos. Please let me explain why your suggestions have no value:
First of all, did you already see there was a button "block image downloads" button in Settings > Advanced? This method ALREADY blocks the visitor from trying to right-click and "download image". Effectively, it does exactly the same as your suggestion, but without the specific layer "hack". This solution is "useful", as it blocks most normal visitors from downloading the photo.
- X3 already does what you suggest, but slightly more elegant.
- Neither the X3 solution or your solution is true protection. The ONLY way to truly protect images (for those who are paranoid about that) is to truly watermark the image.