When an image/attachments with the same file name is being attached to a comment, the previous comment with inline image/attachments will be pointed to the latest updated image so what sees the agent is not what sent the customer.
This is a BUG for the product, there is an open issue to fix it (JRACLOUD-2169, created in 2003!), it has a lot of votes, but yet, priority is low and there are no signs to get it fixed.
My question is... Are you suffering this problem? How do you get around? I'm afraid that current Agents get Customers to bypass the mail integration and asks customers to send the issue with screenshots to their private mail...
I encourage you to go vote for the issue if you are affected by this.
BTW, there is a specific issue for the server edition, which also has the same problem: JRASERVER-2169. Vote for whichever you are affected, or for both! :)