In the template editor, each block has a Conditions menu where you can choose conditions to display the block.
Access your signature templates
From the template menu, choose the desired signature template and click on edit.
Enable/disable conditions
Select a block and click on Conditions.
You have several options:
On all blocks :
You can choose if the block is displayed :
Only on new emails
Only on replies/forwards
On both
Via the add-in:
You can choose on which type of email the template is displayed:
Internally
Externally
On both
On the photo block
You have the possibility to choose the Replace option if your user does not have a photo. In this case, the photo will be replaced by the company logo.