So, there're some images that you'd like to add to your signature but don't have a place to host them. Or you have a host but don't know what to do next?
The easiest and free way to add images to an html signature is to use imgur, a free image hosting.
You can always find icons at services like iconfinder
Lets say you're looking for a new email icon or just want to use your own photo. All you do is just drag and drop the image to the imgur uploader and copy the link.
Then go to the editor's page and just paste the copied image url to the appropriate fields.