In the web world, copyrights and trademarks can get business owners in hot water. Many experienced web developers have an awareness of when legal assistance may be required to resolve such issues.
While I am not an attorney, I can say with a fair degree of certainty what items are safe to use on one’s website.
First and foremost are graphics that you create yourself or have created for you by someone you hire to produce them. However, an exception to that is if the graphic created is similar enough to a copyrighted work to create confusion to the viewer.
Next are photographs. Usually using your own photographs is pretty safe. Photos not taken by you is always risky unless you have permission to do so.
There are various sources on the Internet for pictures and graphics that allow unlicensed or licensed use – otherwise “free to use” graphics or photos. Pixabay.com is one example. It has many items that can be used covering many topics, classifications and so forth.
I recommend you use an experienced, seasoned web developer. A general familiarity with trademark and copyright issues is more apt to be found by using a seasoned website developer. When in doubt, as a business owner you should consult a trademark or copyright attorney.