I used clipart a LOT for newsetters and other documents. I don't always want a photo - clipart is often better at getting an idea across quickly, and I didn't need to worry about copyright because I assumed it was OK to use without permission as it was a part of the MS package. The BING option is terrible - very juvenile and hardly extensive with fewer than 50 options. And by-the-way, most of the online sites for "accessing clipart in MS Word 2010" still say to go to insert then click on clipart. Really - we hardly need such basic instructions when they aren't even correct anymore!
If you mean your own artwork, then you'd take a picture of it, upload it to your computer (make sure you know where you're saving it), then select Insert > Picture in Word, browse in the location where you saved the photo, click the picture, and insert. If you mean an image from the internet or something, you can just save it to your computer and basically follow the rest of the steps above.
Bing Image Search uses a copyright filter based on the Creative Commons licensing system. The results that are returned are images that have been tagged with Creative Commons licenses. A link to the source of the image is provided, which you should use to review the source of the image and the applicable license to determine whether your use will comply with the license. (The settings can be switched to show all web results to view more images.) However, you are responsible for respecting others’ rights, including copyright. Learn more here.
This applies more to teachers than to anyone else, but clip art (especially black line clip art) can´t be beat when it comes to using images that are going to be photocopied. It creates a much cleaner look than a photo. While there is much talk of going digital, the reality is that most of the world still is using paper for teaching . . . and a lot of it, not because we aren´t open to the digital world, but many times not all students have access.
This is TERRIBLE! Besides being able to edit vector images like Will mentioned (which is important for those of us who don't have graphic artists available to create custom images or the budget or time to buy that service ad hoc), you could also search for style "families" (different graphics that were all in the same style). There was a huge range of files and styles in the collection and it was much faster to find what you need than to do a Bing search. Plus, you knew that everything there was free and free to use, without having to worry about CC license issues.