refine prompt again

app.py

@@ -81,7 +81,7 @@ def encode_image(pil_image):
 description_prompt = """
     I want you to imagine how the technical flat sketch of the garment you see in the picture would look like, and describe it in rich details, in one paragraph.
     Don't add any additional comment.
-    Specify that the flat sketch is black and white (even if the original garment has a color), that it doesn't include the person that wear the garment, and that it's not made on a paper sheet, but it's digitally made.
+    Specify that the flat sketch is black and white (even if the original garment has a color), that it doesn't include the person that wear the garment, and that it's not made on a paper sheet, but it's digitally made, so it has plain white background, not paper.
     It should start with "The technical flat sketch of..."