The rapid growth in multimedia based Internet systems and applications like video telephony, video on demand, network based DVD recorders and IP television has created a substantial need for multimedia security. One of the important requirements for multimedia security is transmission of the digital multimedia content in a secure manner using encryption for protecting it from eavesdropping. The simplest way of encrypting multimedia content is to consider the two-dimensional/three-dimensional image/video stream as an one-dimensional stream and to encrypt the entire content using standard block ciphers like AES, DES, IDEA or RC4 or using a stream cipher. The method of encrypting the entire multimedia content is considered as a naive encryption approach. Even though the naive encryption approach provides the desired security requirements, it imposes a large overhead on the multimedia codex. This is due to the size of the multimedia content, and also due to real time requirements of transmission and rendering. Hence, lightweight encryption schemes are gaining popularity for multimedia encryption. Lightweight Encryption schemes are based on the principle “Encrypt minimal and induce maximum noise". Lightweight encryption schemes are designed to take the structure of the multimedia content into consideration. In our work we analyze some of the existing lightweight encryption schemes for digital images and video. The analysis is done based on the amount of security, scalability and effect on compression. A detailed study of some of the existing lightweight encryption schemes is also done by designing cryptanalysis schemes. The cryptanalysis schemes are designed using image noise clearing algorithms and pixel prediction techniques. The designed cryptanalysis schemes reduce the amount of noise introduced by the corresponding lightweight encryption schemes considerably. Based on our analysis of existing lightweight encryption schemes, we propose a set of more robust lightweight encryption schemes for images and video. The proposed lightweight encryption schemes are secure, scalable, and do not degrade the compression achieved. In our work, we also propose a few enhancements to JPEG image compression for achieving more compression, without compromising on the quality. The enhancements to the JPEG compression are extensions of the pixel prediction techniques used in the proposed cryptanalysis schemes.