tl;dr: Can I redirect to a high-res image when people right-click save a thumbnail?
Context
I created a gallery system for my photography business. I'm happy with the results: the gallery can contain over 1000 images and still load fast. I'm using small thumbnails, and lazy loading, it's brilliant.
However one thing I noticed is that people will happily save and share the 30Kb thumbnail by right-clicking it, instead of clicking the "Download" button just below it. And then they share that on social networks. A crappy 800px well-compressed jpg.
I'm very annoyed by this, because: 1. it reflects poorly on my work and 2. people are not getting what they pay for.
Options available
At this point, it seems unavoidable that some customers will only save images by right-clicking them.
I'm aware that I can disable that, but I don't want to do that. I'd be removing features people use and are comfortable with.
I also already have a very visible "Download" button right below the image. Could make it even more visible, but it would become obnoxious.
Question
Can I somehow force people to download the high-res version of the file? I don't mind some level of black magic here, as long as it works, but doesn't load the image until it's saved. Maybe some kind of overlay or javascript, or... Anything goes, really.