adding the logic to generate the image

backend/app/services/qr_service.py

@@ -0,0 +1,19 @@
+from io import BytesIO
+
+import qrcode
+
+
+def generate_qr_image_bytes(text: str, size: int = 300) -> bytes:
+    img = qrcode.make(text)
+
+    # Ensure RGB for consistent PNG output
+    if getattr(img, "mode", None) != "RGB":
+        img = img.convert("RGB")
+
+    if size:
+        img = img.resize((size, size))
+
+    buf = BytesIO()
+    img.save(buf, "PNG")
+    buf.seek(0)
+    return buf.getvalue()