To expand, the fact that the pictures are imperfect quality pretty much is the whole point. The inability to really zoom in, all of the filters that adjust the hue/sharpness, etc are all things that help you hide away imperfections in your photo and draw attention to the broader gist of "look at what I'm eating/where I'm traveling/what I'm doing/how pretty I am!"
The point of Instagram isn't to be able to see the wrinkles in that model's face. The point of Instagram is that you can't see the wrinkles in that model's face.
Ah, that explains why they won't allow you to post photos from their website.
I do some serious-amateur and (when I'm lucky) semi-pro quality photography using a "real camera". I was going to post some of them on Instagram, but discovered that I can't do it except maybe via the phone app. But there's no way I'm shuttling photos from my desktop to my phone so that I can upload them to Instagram.
There is an Instagram app available on the Windows store for some reason. You'd think it would make sense to build a better web client instead, but there you go.
Apparently you can post from the browser if you change your user agent and pretend to be using a mobile browser, so it's specifically desktop browsers that they don't want you to use.
