OCN supports importing images form other URLS and just generates a local copy to OCN's servers. That is how I upload all my images since it guarantees that anyone with access to OCN, can also view images.
The one thing that I can't stand is opening up a high-profile build log only to find all the images are hosted on Dropbox or some other image site that is blocked at my work.
As for the types of screenshots and images that can be posted, anything that obeys the ToS is okay, even if you were to say take a picture of your monitor setup with an copy-righted movie on it playing. Since you're not profiting from it, you aren't breaking the copyright. That is at least the stance I was given when I brought up a similar issue in the past.








