fix typo, alt-text issue and pic suffix

Author: yicw16322

articles/stream-analytics/media/set-up-cicd-pipeline/cmd-script.PNG

@@ -52,21 +52,21 @@ In this section, you learn how to create a build pipeline. You can reference thi
 
    :::image type="content" source="media/set-up-cicd-pipeline/npm-config.png" alt-text="Enter configurations for npm task":::
 
-Use following steps if you need to use hosted-linux agent:
+Use following steps if you need to use hosted-Linux agent:
 1.  Select your **Agent Specification**
 
-    :::image type="content" source="media/set-up-cicd-pipeline/select-agent.png" alt-text="Select agent task":::
+    :::image type="content" source="media/set-up-cicd-pipeline/select-linux-agent.png" alt-text="Screenshot of selecting agent specification.":::
 
 2.  On the **Tasks** page, select the plus sign next to **Agent job 1**. Enter *command line* in the task search and select **Command line**.
 
-    :::image type="content" source="media/set-up-cicd-pipeline/search-cmd.png" alt-text="Select cmd task":::
+    :::image type="content" source="media/set-up-cicd-pipeline/cmd-search.png" alt-text="Screenshot of searching commandline task. ":::
 
 3.  Give the task a **Display name**. enter the following command in **Script**. Leave the remaining default options.
 
       ```bash
       sudo npm install -g azure-streamanalytics-cicd --unsafe-perm=true --allow-root
       ```
-      :::image type="content" source="media/set-up-cicd-pipeline/cmd-script.png" alt-text="Enter script for cmd task":::
+      :::image type="content" source="media/set-up-cicd-pipeline/cmd-scripts.png" alt-text="Screenshot of entering script for cmd task.":::
 
 ## Add a Build task