How to add a picture to the signature
See extract from below eM Client thread.
Paul_Technical_Support
https://forum.emclient.com/t/cant-add-image-to-signature/40059
“To add an image to your signature, please right click the signature editor and select Insert > Image or click on the Image icon in the Toolbar to select an image from your computer”.
“You can also link to eternal files using HTML formatting, in case you’d like to include an HTML image, right click the signature editor and select HTML in the “Insert” dropdown menu”.