Update app.py

app.py

@@ -348,7 +348,7 @@ def generate_certificate(certificate_model, first_name, last_name):
     rgb = Image.new('RGB', im.size, (255, 255, 255))  # white background
     rgb.paste(rgba, mask=rgba.split()[3]) # 3 is the alpha channel
     pdf_ = rgb.save("certificate.pdf", 'PDF', save_all = True, resolution=100.0)
-    pdf__ = im.save("certificate.pdf", 'PDF', save_all = True, resolution=100.0)
+    pdf__ = im.save("certificate.png")
     print("RGB", rgb)
     print("PDF", pdf_)
     print("PDF", pdf__)