Are Bloggers Working Legally?

After reading some of my favorite blogs yesterday I realised there is an issue that could possibly land the blog community in hot water. Blog transcripts are often accompanied with images, this is natural as they fill space and bring some vitality to a post. The point I would like to raise is, are all these images free from copyrite restrictions or are they are just copied from another online source without taking this important factor into consideration. What would prevent the owner of the images/snapshots starting legal proceedings for copyrite infringements     ?

Of course I am well aware the vast majority of site owners would be more than happy with their images or snapshots displayed elsewhere, why should they object, it's good advertising, that said this may not be the case all of the time.

In terms of written content, it's easy to find out if work has been replicated, by the use of Copyscape, this is not the case with the misuse of imagary.

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