fix: added type to st.file_uploader

dashboard_featurefinder.py

@@ -89,7 +89,7 @@ def app():
         aerial photographs. You will need to download from Unsplash to your 
         computer and upload it to the demo app.
     """)
-    buf = st.file_uploader("Upload Image for Analysis")
+    buf = st.file_uploader("Upload Image for Analysis", type=["png", "jpg"])
     searched_feature = st.text_input("Feature to find")
     if st.button("Find"):
         ftmp = NamedTemporaryFile()