update lock-unlock (#2947)

* Update overview.mdx

* Add files via upload

* update image

Author: gfletcher-cll

public/images/ccip/cct/handling/lock-unlock.png

@@ -127,9 +127,9 @@ Tokens are burned on the source blockchain (which is the non-issuing blockchain)
 
 ### Lock and Unlock
 
-Tokens are locked on the source blockchain, and an equivalent amount of tokens are released on the destination blockchain. This use case is not recommended, as it implies multiple issuing blockchains, which results in fragmented liquidity as well as the requirement of managing liquidity to ensure liveness of lanes. For additional guidance on Lock and Unlock configuration, please review best practices.
+Tokens are locked on the source blockchain, and an equivalent amount of tokens are released on the destination blockchain. For additional guidance on Lock and Unlock configuration, please review best practices.
 
-<ClickToZoom src="/images/ccip/cct/handling/lock-unlock.jpg" alt="CCIP Lock and Unlock mechanism" />
+<ClickToZoom src="/images/ccip/cct/handling/lock-unlock.png" alt="CCIP Lock and Unlock mechanism" />
 
 ### Token-Specific Transfer Mechanisms