Fix image file pointer issue and add validation

app.py

@@ -226,8 +226,15 @@ with col1:
         help="Upload a chest X-ray image in PNG, JPG, or JPEG format"
     )
     if uploaded_image:
-        image_preview = Image.open(uploaded_image).convert("RGB")
-        st.image(image_preview, caption="Uploaded X-ray", use_container_width=True)
+        try:
+            # Reset file pointer to beginning
+            uploaded_image.seek(0)
+            image_preview = Image.open(uploaded_image).convert("RGB")
+            st.image(image_preview, caption="Uploaded X-ray", use_container_width=True)
+            # Reset again for later use
+            uploaded_image.seek(0)
+        except Exception as e:
+            st.error(f"Error loading image: {str(e)}")
     st.markdown('</div>', unsafe_allow_html=True)
 
 with col2:
@@ -270,13 +277,22 @@ st.markdown("<br>", unsafe_allow_html=True)
 analyze = st.button("🔍 Analyze Case", use_container_width=True, type="primary")
 st.markdown("<br>", unsafe_allow_html=True)
 
+# Validation message
+if analyze:
+    if not uploaded_image:
+        st.warning("⚠️ Please upload a chest X-ray image")
+    if not findings or not findings.strip():
+        st.warning("⚠️ Please enter radiology findings")
+
 # --------------------------------------------------
 # Inference + Explainability
 # --------------------------------------------------
-if analyze and uploaded_image and findings:
+if analyze and uploaded_image and findings and findings.strip():
     with st.spinner("🔄 Analyzing case... This may take a few moments."):
         try:
             # ---- Preprocess inputs ----
+            # Reset file pointer to beginning
+            uploaded_image.seek(0)
             image = Image.open(uploaded_image).convert("RGB")
             image_tensor = image_transform(image).unsqueeze(0).to(device)