If you're looking for an API to check if people are using your brand's images fraudulently, TinEye has a mature service. It combines computer vision and machine learning technology for fast and accurate image searches, which makes it useful for content moderation and fraud detection. TinEye's Advanced Image Identification can help you monitor image usage and find unauthorized uses of your brand's images.
Another good option is Visionati, a general-purpose visual analysis service that includes brand and logo detection. It offers an API for developers who want to customize the analysis and image descriptions. Visionati's digital marketing and data analysis tools can help you identify and take action against fraudulent use of your brand's images.