Image adder and subtractor based on light storage Tianhui Qiu, Hongyang Ma, Peipei Xin, Xiaolong Zhao, Qian Liu, Libo Chen, Yuncai Feng and Zhixian Yu Eur. Phys. J. Plus, 137 1 (2022) 126 Published online: 17 January 2022 DOI: 10.1140/epjp/s13360-022-02338-x