Well, basically it is. You have to be very careful what you post these days. You can always download an image from some free stock website, but many of them are still not free at all. For Example, you can use an image you download from a website, but you need to leave a backlink to their site. Or you even can't dowload the image, but you have to purchase it. You can still find free images, but make sure you read their terms of use - sometimes their copyright statement is something like: License: Non commercial use, reference use only. If you have a disclaimer on your website stating something like: If you own one or more of these images, email me and I will delete as soon as possible. This might help, but always make sure you know from where your images come from. You can have copyrighted images on your site for 10 years without and problem, just as you can get sued in 1 week. Hope this helps.
Of course it is illegal! Disclaimers do not protect you. The disclaimer that theAnimatorGuy suggests will NOT protect you and will have the opposite effect of making your legal situation worse. Its suggest that you know that what you are doing is illegal, but you doing it until caught!
Agent000, I didn't say it WILL protect him, and it MIGHT have the opposite effect. Because if he doesn't have anything like it and he will keep adding copyright images - Ignorance will be far worse than immiadiate image cancellation. But you are right, the suggestion of knowing its illegal and still doing it can be more devastating. It all depends on current situations - but its always better to do legal and ethical bussiness.
You cant use anything with copyright , images , videos, scripts, nothing, if you dont pay for this or have the rights to sell or give it free.
All a disclaimer does is say that someone else is using something at their own risk. It doesn't stop you from being liable for copyright infringement.
I think that if you don't want to make a deal with some photo agency which will give you the license to use their pictures, I would recommend to use free images like Flickr. I'm not sure about Pinterest but I think that they are in some kind of grey zone for now, and let we be sincere, it is always nicer to see some amateur image in articles then a professional photo, of course depending what kind of website you own.
Flickr is not necessarily free. You have to be very careful. There are some public domain and free photo sites but you need to be careful where you go.
Make sure before you post that image that the owner of the image agrees to let you do that. Other than that it is an infringement, and you will have to pay a lot of money, or if you own a business, you can go bankrupt
I only use free stock images from sites and give attribution as required. This site looks good: http://freestockphotosgallery.godotmedia.com/ . they have high resolution images for free and only need attribution