I did not understand your great idea, can you be more precise > the transparent layer is to avoid the temporary file to be kept in the computer's memory?
SO, if I understood well, the question of protecting photos is completely impossible, in any kind of site, even with diaporama, apart from marking them with watermark- thaanks for your indications !
No, the image is still "cached" in the computer.
The translucent overlay just ensures that a "right-click" cannot be applied to the underlying image.
However, "right-clicking" is not the only way to grab that image as it MUST be downloaded to your computer before your browser can display it, and if it is in your computer it can be copied.
As has been stated many times in this forum, you can make it harder, but you cannot prevent an image from being copied.
Well, as long as you remember that it's a losing battle, you can go to Album > Settings > Turtle > Advanced, and check "Right click protect." But anyone who wants to grab your images will still be able to, by various other means.