fix some bugs

app.py

@@ -75,9 +75,19 @@ css = """
 """
 # max-heigh: 1500px;
 
-_HEADER_ = '''
-<h2><b>Official 🤗 UltraHDR Demo</b></h2><h2><a href='' target='_blank'><b>UltraHDR: xxx</b></a></h2>
-'''
+_HEADER_ = r"""
+<h1 style="text-align: center;"><b>UltraFusion</b></h1>
+
+- This is an HDR algorithm that fuses two images with different exposures.
+
+- This can fuse two images with a very large exposure difference, even up to 9 stops.
+
+- The maximum resolution we support is 1500 x 1500. If the images you upload are larger than this, they will be downscaled while maintaining the original aspect ratio.
+
+- The two input images should have the same resolution; otherwise, an error will be reported.
+
+- This is only for internal testing. Do not share it publicly.
+"""
 
 _CITE_ = r"""
 📝 **Citation**
@@ -103,7 +113,7 @@ If you have any questions, feel free to open a discussion or contact us at <b>xx
 
 with gr.Blocks(css=css) as demo:
     with gr.Column(elem_id="col-container"):
-        gr.Markdown(" # UltraHDR")
+        gr.Markdown(_HEADER_)
         with gr.Row():
             under_expo_img = gr.Image(label="UnderExposureImage", show_label=True,
                 image_mode="RGB",