“But it didn’t look like I had to pay anything!” isn’t going to fly as an excuse.
Do you randomly download photos from Google images or who-knows-where-else and put them on your website? Yeah, you probably want to stop doing that. In fact, you probably want to go look through every single photo you have on your website and make sure yo have the rights to use it. You should probably do that sooner than later. Now is a good time.
Or you could wait around for the owners of the stock photo to come and find you. Because they will. It’s not a question of if but when. They have time. In fact, they’ll back charge you for the time you’ve had the photo on your site. Not sure how they can figure that out exactly, but it’s probably not too hard. It’s the Internet, right? You can figure out anything.
How can you be safe?
Safest bet is to use … your own photos. That you took with your own camera. Then you know. If you don’t have what you need, go to a reputable stock photo site, shop around, and pay for the rights. Read what rights you’re paying for: are they digital? Are you allowed to use it in print as well? On personal sites or business? Or both? Can you use it to make your logo and make that your business brand? Read the fine print. I know, it’s no fun, but it’s less fun to get a letter in a few years requesting, albeit politely, to pay in arrears for the time you’ve been illegally using the photo you didn’t quite have the rights for.
If you do go the freebie route, just make sure you’re truly allowed to use the photos for what you want to use them for. Also, do you need to credit the owner? Do you need to do it right there where the photo is or can you create some sort of “Credits” page on your site to do so? Again, read the fine print, play it safe … better safe than sorry, right? Uh huh.