This book constitutes the refereed proceedings of the 15th Conference on Image and Graphics Technologies and Applications, IGTA 2020, held in Beijing, China in September, 2020.*The 24 papers presented were carefully reviewed and selected from 115 submissions. They provide a forum for sharing progresses in the areas of image processing technology; image analysis and understanding; computer vision and pattern recognition; big data mining, computer graphics and VR, as well as image technology applications. *The conference was held virtually due to the COVID-19 pandemic.