If you are using Redtail's internal email client to send individual emails or Broadcast Emails, and want to add an image to your signature, you can do so by adding this within the Email Options section of your Site Preferences:
You can see in the highlighted area above that I've already added the text portion of this signature.
Now, how do you get your image uploaded so that it will be included with your signature as well?
First, click inside your signature box so that your cursor is blinking in the approximate location where you'd like to place the image. Then, click the Insert Image icon in your Email Signature toolbar:
You'll then be presented with a modal like the one below:
Note the URL box that I've highlighted in yellow above. To insert an image in your signature file, it must appear online somewhere so that you can copy the image's URL for insertion here. So, locate your desired image online and then copy its URL and paste it into this box, as in the example below:
Then, click OK.
Your image should then show up in your Email Signature box.
Just click Save Preferences in the upper right-hand corner of the Email Options box and your signature with the image will be included on all future emails originating from Redtail's internal email client.