In other words, it belongs to someone else and if you use it without their permission for say business purposes – you could get into some hot water.
There are many places that legitimately sell stock pictures for you to use for your website/book covers/banner, etc. The problem is that it's really, really ridiculously expensive. Most of them have you sign up for a month/yearly subscription, or if you buy one at a time – they zing you with high price.
I find Canstock to be the most affordable and they have the exact – identical stock photos all the other expensive site have at fraction of the cost.
You can sign up for membership for little as one week or you can just buy credits. They have a plan for almost every type of buyer, from the occasional user to the mega user. I use the credit method as it is the most convenient for me.
The number of credit used for each purchase range from as little as two for a small or 10 for the xxlarge tiff file. For most books, banners & website the medium or large at 3 to 4 credit works just fine.
You can buy credits which does not expire so you use it when you need it. I use mine in large quantity all at once then won't need it again for a long time but the credits remain – which I just love.
They also allow members to have a random free download – typically a theme of the month like Christmas and other major holidays.
You can also favorite any pictures you like and sort it however you need to for later use.
I give this site an A+.
Don't get caught with using illegal stocks – it could be embarrassing when you get a notice from the actual owner of the picture or photo with a take down notice. Do it the right way and buy it on any of the stock photo sites.
There is another site called the dollar stock photo – I haven't tried them yet. They do look promising. I'm a fan of Canstock, they are just as good as Shutterstock with better pricing!