update per suggestion

Author: iriaosara

articles/managed-instance-apache-cassandra/best-practice-performance.md

@@ -90,12 +90,12 @@ Our default settings are already suitable for low latency workloads. To ensure b
 
 Like every database system, Cassandra works best if the CPU utilization is around 50% and never gets above 80%. You can view CPU metrics in the Metrics tab within Monitoring from the portal:
 
-   :::image type="content" source="./media/best-practice-performance/metrics-cpu.png" alt-text="Screenshot of CPU metrics." lightbox="./media/best-practice-performance/metrics-cpu.png" border="true":::    
+   :::image type="content" source="./media/best-practice-performance/metrics-cpu.png" alt-text="Screenshot of CPU metrics by idle usage." lightbox="./media/best-practice-performance/metrics-cpu.png" border="true":::    
 
    > [!TIP]
    > For a realistic CPU view, add a filter and split the property by `Usage kind=usage_idle`. If this value is lower than the required CPU, you can apply splitting to obtain usage by all usage kinds.
 
-   :::image type="content" source="./media/best-practice-performance/metrics-cpu-by-usage.png" alt-text="Screenshot of CPU metrics." lightbox="./media/best-practice-performance/metrics-cpu-by-usage.png" border="true":::
+   :::image type="content" source="./media/best-practice-performance/metrics-cpu-by-usage.png" alt-text="Screenshot of CPU metrics by usage kind." lightbox="./media/best-practice-performance/metrics-cpu-by-usage.png" border="true":::
 
 If the CPU is permanently above 80% for most nodes the database becomes overloaded manifesting in multiple client timeouts. In this scenario, we recommend taking the following actions: