Problem that I've with this functionality is that it must be limited in some way. Either you will be allowed to download your own albums or to have a queue system to deliver the files because it is a huge potential bottleneck to DDoS attacks. Zipping large albums is an expensive task for the machine and if this album has images in external storage is also a huge task for the network interface.
I'm aware that the idea of this is to be able to download albums and maybe download selected images or albums. But like I said, it won't work like that because the potential to break the website is large and I don't want to open that opportunity for attackers. Chevereto based websites trends to be huge websites so I can't just pop out a feature that could compromise those systems.