Merge pull request #1992 from OffchainLabs/diagrams-update-1

docs: updating inforgraphics and diagrams

Author: anegg0

arbitrum-docs/assets/geth-sandwich.png

@@ -51,7 +51,7 @@ When it comes to implementing the protocol, BoLD needs to be deployed on a credi
 
 A helpful mental model for understanding the system is that it uses Ethereum itself as the ultimate referee for deciding assertion results. Participants in the challenge protocol can disagree over the _results of L2 state transitions_ and provide proofs to the protocol's smart contracts on Ethereum to determine which result is correct. Because computation is deterministic, there will always be a single correct result.
 
-![900px-img](../assets/KSf_Image_1.png)
+![900px-img](../assets/transaction-lifecycle.svg)
 
 _From the **[Nitro whitepaper](https://github.com/OffchainLabs/nitro/blob/master/docs/Nitro-whitepaper.pdf)**. L2 blocks are “settled to L1” after a 6.4 day period has elapsed and nobody has challenged their validity on Ethereum._