I've been looking around for a while for a very basic site to upload design images to and share with my team or clients.
There are a lot of options out there, but I've yet to find one that displays the images the right way. Generally, they'll keep the image (which is usually a very long image - think 5000px height) contained within the viewport, and then when you zoom in on it, it overflows the viewport.
Dribbble is the only option I've found that does a good job at displaying UI designs correctly, but then there's the problem of you have to be a player or on a team. Not only that, but sometimes your designs aren't ready for the world to see and when you upload to Dribbble, it's completely public.
InvisionApp is another option that works well. But, it's very bloated and made specifically for prototyping. You can do it and it'll work, but it's going to take you a while to get to a point where you're ready to share anything. Not to mention that you'll only be able to upload screens to a single project (unless you want to pay).
So, I took matters into my own hands and made a very lightweight app solely focused on displaying UI designs correctly.
You get two things on Knuvo, an Image List and an Image Page.
Your image list is completely private to your user account and only you can view your list.
Your image page is public but only accessible via the link. It won't magically show up in somebody else's list unless you share the image with them and they add it themselves.
You can check out an example Image Page here: knuvo.co/5/NhB9mJrvHbNidpTss
I made this to benefit myself, but if anybody else wants to use it as well, have at it! Feel free to let all your designer friends know about it.