Image enhancement involves techniques employed to improve the digital quality of images, particularly those of poor quality. One specific method discussed is contrast enhancement, which aims to produce clearer images by redistributing brightness intensity values. This enhancement process utilizes feature optimization techniques, notably particle swarm optimization, to effectively select both local and global features of an image. The optimized features are then applied across the entire image, resulting in improved quality. Experimental results indicate that the proposed threshold-based enhancement algorithm for mixed digital images performs better than traditional methods, especially in cases with heavily damaged pixels, demonstrating its effectiveness in complex scenarios.