Adding diagram title and alt-text, and final checks.

Author: madeline-underwood

content/learning-paths/servers-and-cloud-computing/spark-on-gcp/benchmarking.md

@@ -34,7 +34,7 @@ This compiles Spark and its dependencies, enabling the benchmarks build profile
 ```  
 This executes the `AggregateBenchmark`, which compares performance of SQL aggregation operations (e.g., SUM, STDDEV) with and without `WholeStageCodegen`. `WholeStageCodegen` is an optimization technique used by Spark SQL to improve the performance of query execution by generating Java bytecode for entire query stages instead of interpreting them step-by-step.
 
-### Example Apache Spark benchmark output (Arm64)
+## Example Apache Spark benchmark output (Arm64)
 You should see output similar to:
 
 ```output
@@ -236,7 +236,7 @@ You should see output similar to:
 [success] Total time: 669 s (11:09), completed Jul 24, 2025, 5:41:24 AM
 
 ```
-### Understanding Apache Spark benchmark metrics and results
+## Understanding Apache Spark benchmark metrics and results
 
 - **Best Time (ms):** Fastest execution time observed (in milliseconds).
 - **Avg Time (ms):** Average time across all iterations.

content/learning-paths/servers-and-cloud-computing/spark-on-gcp/instance.md

@@ -22,7 +22,7 @@ To create a virtual machine based on the C4A Arm architecture:
    - Set **Series** to `C4A`.
    - Select a machine type such as `c4a-standard-4`.
 
-   ![Instance Screenshot](./image1.png)
+   ![Create a Google Axion C4A Arm virtual machine in the Google Cloud Console with c4a-standard-4 selected alt-text#center](./image1.png "Google Cloud Console – creating a Google Axion C4A Arm virtual machine")
 
 4. Under **OS and Storage**, select **Change**, then choose an Arm64-based OS image.  
    For this Learning Path, use **Red Hat Enterprise Linux 9**. Ensure you select the **Arm image** variant. Click **Select**.