Update image_caption_gui.py

Signed-off-by: Victor Hall <victor.charles.hall@gmail.com>

scripts/image_caption_gui.py

@@ -13,7 +13,7 @@ from tkinter import filedialog
 from PIL import Image, ImageTk
 from pathlib import Path
 
-IMG_EXT = ["jpg", "jpeg", "png"]
+IMG_EXT = ["jpg", "jpeg", "png", "webp"]
 
 class CaptionedImage():
     def __init__(self, image_path):
@@ -158,4 +158,4 @@ if __name__=='__main__':
 
     view = ImageView(root)
     view.pack(side=tk.TOP, fill=tk.BOTH, expand=True)
-    root.mainloop()
+    root.mainloop()