Recent advances in imaging and computing technology generate tremendous image data daily. Searching image collections has been made easier with the introduction of some content-based image retrieval (CBIR) approaches. The research area of CBIR is currently an active topic. It is becoming increasingly important to process and store big data in a parallel and distributed manner using CBIR, especially cloud computing platforms. Cloud computing provides high amounts of computation power that can be accessed at low costs. However, cloud servers are not entirely secure, and data owners raise privacy concerns; thus, the encrypted image and encrypted feature are uploaded to the cloud server to ensure privacy. This paper presents the essential techniques of secure content-based image retrieval over cloud computing. We will compare and contrast several approaches for CBIR, especially with cloud computing.