To be honest, I have no idea what Zenfolio is?
So I tickled google, and it looks like some sort of a web location for people to display their work?
If so, then the simple rules are likely the same. 800 x 600 size images uploaded to your page?
Every line above ends in a ?? because I don't know if I am reading your words right/
Qimage makes perfect downsized images perfect for uploading.
Simply click on make Email and Web copies, set the size you want, and say NO when it asks if you want to email.
The downsized images will appear in a sub folder.
If you need tighter help, just holler.
Fred