added imshow visual test for percy

Author: emmanuelle

test/percy/plotly-express.py

@@ -341,6 +341,14 @@
 )
 fig.write_html(os.path.join(dir_name, "line_ternary.html"))
 
+import plotly.express as px
+import numpy as np
+img_rgb = np.array([[[255, 0, 0], [0, 255, 0], [0, 0, 255]],
+                    [[0, 255, 0], [0, 0, 255], [255, 0, 0]]
+                   ], dtype=np.uint8)
+fig = px.imshow(img_rgb)
+fig.write_html(os.path.join(dir_name, "imshow.html"))
+
 # #### 3D Coordinates
 
 import plotly.express as px