Pligg Support

I hope someone can help. I am setting up a bookmarking site and I am concerned about using, or allowing members to add, images that are from an article or website. There are so many rules about incorrectly using images, I want to make sure I don't accidentally get into trouble. I see DIGG uses images all the time, seems to use screenshots. If the image is available from the source url, is it OK to add it to the post?
Would really appreciate some help on this one - I'm afraid to move forward with this site development until I understand the regulations more.
I'd like to have users submit articles they write, with images. I realize I can modify the code to do this and it shouldn't be very much work, but has anyone already done this? I'd like a WYSIWYG tool so users don't need to use HTML and can upload images/video.