Fix figure caption (left-to-right)

README.md

@@ -58,7 +58,7 @@ Collecting spatially consistent multi-modal remote sensing (MMRS) images remains
 </div>
 
 <p align="center"><img src="assets/show.png" alt="Generated multi-modal remote sensing images" width="900" /></p>
-<p align="center" style="margin-top: -10px;"><span style="color: gray; font-size: 14px;">From top to bottom: optical (OPT), synthetic aperture radar (SAR), and near-infrared (NIR) images.</span></p>
+<p align="center" style="margin-top: -10px;"><span style="color: gray; font-size: 14px;">For each group, from left to right: optical (OPT), synthetic aperture radar (SAR), and near-infrared (NIR) images.</span></p>
 <div align="left">
 
 ## Dataset Overview