Zenni as well here. Overall I'm happy. To answer your question: the website has a semi-functional "virtual try-on" that works well enough for checking the look of glasses. I only used to it gauge the size of them, because I have a big head.
Worth noting that if you have a strong prescription, you're going to pay more wherever you buy them. I have a -4.5 cyl number, and the glasses I wear now cost around $100, despite the frames starting at like $25
You're not wrong. I would say they're functional junk. They're definitely cheap, but they got my prescription spot-on , and it took me like 4 months to notice the slight warping on the lens. If they weren't all I can afford, I would buy from elsewhere, but they aren't the worst thing I've had to compromise on for price. I wish my cheap junker car worked as well as these glasses.