Revert "tiproxy: fix image link in tiproxy-load-balance.md (#21205)"

This reverts commit 2d585aa.

Author: hfxsd

tiproxy/tiproxy-load-balance.md

@@ -43,7 +43,7 @@ Consider an application that handles both transaction and BI workloads. To preve
 4. Optional: For storage layer isolation, configure [Placement Rules](/configure-placement-rules.md) or [Resource Control](/tidb-resource-control-ru-groups.md).
 5. Direct transaction and BI clients to connect to their respective TiProxy instance addresses.
 
-<img src="https://github.com/pingcap/docs/blob/release-8.5/media/tiproxy/tiproxy-balance-label.png" alt="Label-based Load Balancing" width="600" />
+<img src="https://docs-download.pingcap.com/media/images/docs/tiproxy/tiproxy-balance-label.png" alt="Label-based Load Balancing" width="600" />
 
 Example configuration for this topology: