changing case of png and referencing in main doc as well

Author: jammul1

articles/app-service/routine-maintenance.md

@@ -36,7 +36,7 @@ In order from top to bottom, the example shows:
 
 The following screenshots show additional information available through the Impacted Resources dropdown:
 
-:::image type="content" source="./media/routine-maintenance/routine-maintenance-first.png" alt-text="Screenshot of the Impacted Resources blade in the Azure portal.":::
+:::image type="content" source="./media/routine-maintenance/routine-maintenance-first-page.png" alt-text="Screenshot of the Impacted Resources blade in the Azure portal.":::
 
 In order from left to right, the example shows: