An image processing method and system removes block artifacts in compressed image/video. Block artifacts are detected based on content analysis performed based on knowledge of the contents of the image/video. Then, a set of priority conditions is evaluated to generate a detection decision for each pixel at the block boundary. A higher priority is given to a short-term temporal processing result and a spatial processing result. The long-term temporal processing result and quantization information are treated as auxiliary information to adjust the strength of filtering. Depending on the result of the detection decision, appropriate filtering is applied to the pixel to remove the block artifacts.