To reference an image properly, you will need to find the original source of the image. Referencing an image found in a container such as Pinterest is not an acceptable reference.
You might also want to do a reverse image search to verify its authenticity.
The best way to find the original source of an image is to do a reverse image search.
Upload the image into one of the following links use some detective skills to find the original source.
Here are some instructions for doing reverse image searches on your mobile.