MADISON, Wis. -

Some Facebook users may be eligible to receive up to $10 each from a settlement of a class-action lawsuit over Facebook's "Sponsored Stories" ads.

Like the millions of users on Facebook, Caroline Radaj posts photos.

"I have a lot of Badger pictures (posted)," said Radaj, a recent graduate of the University of Wisconsin-Madison.

Radaj received an email claiming to be from Facebook saying her photos may have been used in ads for the social media site. The email included instructions on how to cash in on a $20 million settlement over Sponsored Stories ads that included users' images without their permission.

Even after reading the fine print, Radaj, who works in advertising herself, said she had her doubts.

"I thought it was spam, to be honest with you, because Facebook is decently open with things that are majorly happening," Radaj said. "And I have gotten spam emails before and I thought this was just another one."

But the email was in fact from Facebook, which found itself facing a class-action lawsuit for using photos in ads without consent. Those who submit a valid claim are eligible for up $10.

"We're in a very quickly changing environment here," said Kim Hazen with Wisconsin's Better Business Bureau.

Hazen said laws over creative ownership on social media continue to evolve and Facebook's settlement fund is just the beginning.

"Unfortunately, there are always going to be operators who believe it's easier to ask for forgiveness than permission," said Hazen. "Because we don't want to go out and ask millions, 'Hey, can I use that picture of grandma on an ad?' What are you going to say? No."

"I had no idea what was going on," said Radaj. "And now, I think more people are going to start to know it's important to (be aware of) what they're putting on (social media)."

The money from the settlement depends on how many people submit claims.

For more on the background of the case, the terms of the settlement, and forms you need to fill out, go to www.fraleyfacebooksettlement.com.

The claim must be filed by May 2. Doing nothing means you're giving up any right to sue Facebook over this issue.