Want to avoid a potential lawsuit? Stay away from websites offering free images, and do not randomly copy images you find on other sites and post them to your blog. It’s not worth the risk.
The legal responsibility for illegally using a photo in any on or offline site or publication always falls on the publisher, regardless of them being unaware of said infringement. That’s you! Unless the owner of the photo has consented to allow you to use it, you are not protected. Not only do you risk a potential lawsuit from the owner of the photo, but you also risk a potential lawsuit from any models who may be in the photo.
Don’t believe what you may read on some blog posts where they say it’s ok to use an image you found online as long as you give credit to the source. Giving credit to the source does not protect you from copyright infringement. Save yourself the worry and use a legitimate stock image resource like ShutterStock to purchase your photos from. All professional stock photography suppliers will have all Model Releases documented along with all other legal usage contracts in place to protect you from any copyright infringement claims. Yes, you will have to pay a few bucks, but it’s worth the peace of mind.
You also have the option of taking your own photos, just make sure that you have model releases from any people you include in the photo (if they are close enough to be recognizable) and don’t include any landmarks or buildings which may be copyrighted.