Images are an important part of any online article. Text only without photos or clip arts looks boring and doesn't attract readers - it may even drive them away on first glance. But where can we find suitable images? Not only since SOPA, ACTA and PIPA, novel strict copyright protecting legal bills, using images - e.g. from Google Image Search - without permission of the copyright holder often results in dramatically high fines!
But there's a simple solution to that: use copyright free public domain images ... or if your desired object is not available as such, use images under a Creative Commons attribution license. The second suggestion requires you to mention photographer and source of the file adjacent to the image.