Agent's photo in the signature
The easiest solution on how to add Agent's photo into the signature part of the ticket is to use variable {$agentAvatarUrl} in Configuration --> Email --> Customer Templates --> choose the template. If you will add only the variable {$agentAvatarUrl}, this will return just the URL address. Therefore, please use the variable together with the HTML code for embedding an image, as shown in the example below (you can edit the link and/or add more style elements, based on your style preference):
Example
<img src="{$agentAvatarUrl}" style="max-width: 80px; max-height: 80px;" />
Smarty signature
The following information shows you how to use "IF" logic, in case you wish to have it displayed only for a particular agent or you want to display a different photo instead of Agent's own Avatar. The trick is, that we will define custom HTML for each agent directly in the email template (e.g. Reply template or New email template). Email templates support Smarty programming language, which helps you to define simple constructions like IF ... ELSE.
Here is short code you can use in the email template:
{if $agentLastName eq 'Lastname1'} html signature for agent with Lastname1 {elseif $agentLastName eq 'Lastname2'} another html signature for agent with Lastname2 {/if}
Now you can define a custom HTML signature for each agent separately: