In many of today's consumer electronics products, high-definition digital images have become a main source of information. As the demand of high quality of images keeps increasing, the reduction of image noise becomes a primary topic. In this thesis, we design several approaches for the reduction of Gaussian noise, impulse noise, and compression artifacts. First, images with unknown type of noise would be processed for the detection of compression artifact and impulse noise. The proposed methods are then used to enhance image quality. For practical applications, the proposed algorithms do not require any coding information, and can be directly applied over decompressed data. The proposed methods require low computational loads and hardware resources, and can be efficiently applied to various kinds of color images and videos.