Update README.md

README.md

@@ -1,3 +1,16 @@
----
-license: apache-2.0
----
+---
+license: apache-2.0
+---
+
+## Citation
+```
+@misc{kang2025legionlearninggroundexplain,
+      title={LEGION: Learning to Ground and Explain for Synthetic Image Detection}, 
+      author={Hengrui Kang and Siwei Wen and Zichen Wen and Junyan Ye and Weijia Li and Peilin Feng and Baichuan Zhou and Bin Wang and Dahua Lin and Linfeng Zhang and Conghui He},
+      year={2025},
+      eprint={2503.15264},
+      archivePrefix={arXiv},
+      primaryClass={cs.CV},
+      url={https://arxiv.org/abs/2503.15264}, 
+}
+```