There are many legal and ethical issues unique to online journalism. Let’s review a few issues:
Great summation of problems with defamation online and off.
Here is a local example:
Gawker’s big mistake
Great Review of Copyright law
When looking for images the key words for you are:
Limited copyright – some rights reserved
Flickr is a great site for free photography with for non commercial use like a blog or news story.
All media sites have what is also called a Terms of Service.