add download button

app.py

@@ -29,7 +29,7 @@ show_dt = st.checkbox("Show timestamp", True)
 
 fetch_data = st.checkbox("Refresh data", False)
 
-if st.button("Plot Data"):
+if st.button("Create GIF"):
     smoke_url = "https://firesmoke.ca/forecasts/current/dispersion.nc"
     smoke_nc = "./data/dispersion.nc"
     if not os.path.isfile(smoke_nc) or fetch_data:
@@ -94,7 +94,12 @@ if st.button("Plot Data"):
     last_dt = dts[-1]
 
     st.image(buffer, caption=f"{first_dt} to {last_dt}")
+    st.download_button(
+        label="Download GIF", data=buffer, file_name="firesmoke.gif", mime="image/gif"
+    )
 
     with st.expander("Data Sources"):
         st.markdown(f"Smoke forecast: [FireSmoke Canada](https://firesmoke.ca/)")
-        st.markdown(f"Administrative boundaries: [Natural Earth, 1:50M Admin 1 – States, provinces](https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/cultural/ne_50m_admin_1_states_provinces.zip)")
+        st.markdown(
+            f"Administrative boundaries: [Natural Earth, 1:50M Admin 1 – States, provinces](https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/cultural/ne_50m_admin_1_states_provinces.zip)"
+        )