exif fix for webp

* fix for odd error only in webp files whereby piexif.insert inserts the bytes correctly, but image.save inserts extra "Exif" in the image metadata which results in an error on reading

modules/images.py

@@ -356,6 +356,9 @@ def save_image(image, path, basename, seed=None, prompt=None, extension='png', i
 
     image.save(fullfn, quality=opts.jpeg_quality, pnginfo=pnginfo, exif=exif_bytes)
 
+    if extension.lower() == "webp":
+        piexif.insert(exif_bytes, fullfn)
+
     target_side_length = 4000
     oversize = image.width > target_side_length or image.height > target_side_length
     if opts.export_for_4chan and (oversize or os.stat(fullfn).st_size > 4 * 1024 * 1024):