I totally agree, as I outlined this is more for a deterrent than actual protection. I am fully aware how easy it is to get images from the computers cache files, and how easy it is to foil, which I thought I had outlined in my post.
This was simply a recommendation, as not all users of ZenPhoto I would guess are familiar with scripting of templates/themes to make the changes themselves. And would much prefer simple clickable option to enable/disable, rather than playing around with code, that they either not familiar or do not understand (although it is well document within ZenPhoto User Guides).
Also if this was added within zp-core, it would work across themes regardless. As it’s the core that is building `<img />` string.
However I have made my changes and it works for me. I just thought I would offer a suggestion.