Freak has a lot of free content, but those pictures with a crown are from the premium plan, and if you buy it, you can use the pictures without attribution.
But when you download a free image, the site itself reminds you that you must indicate the creator of the work.
For commercial and personal projects
On digital or printed media
Unlimited once and for all
Anywhere in the world
To create modifications and derivative works
Read here: Freepik Company