This is a simple extension. This will add a Author name at the end of the post. You can set any Font you need since this will create image on the fly with the font you provided.
Currently am adding 3 fonts. All of them are downloaded from Font Space from where you can download fonts for free.
How to use
1. Download the attached zip file
2. unzip it
3.Signinjector .cs to Extension folder
4. Fonts folder to the App_Data Folder
5. SignImage.aspx and SignImage.aspx.cs to the root folder
thats all.
on the SignImage.aspx.cs find the line Font f = new Font(privateFonts.Families[0], 50,FontStyle.Bold,GraphicsUnit.Pixel); Change that 50 to change the font size.
This will create sinature with random fonts which you added in the fonts folder.
Currently it will add signature to all posts even they are just a description of the post. If you have 10 posts on home page it will display 10 signatures (1 under each post). If you need signature on the page which will display only one post, then remove the commented portion on Signinjector .cs and comment or remove the un commented section.
Comment or remove from if (e.Location != ServingLocation.SinglePage) to }, and Uncomment Remove /* and */
I know this is not a big deal 
, still am learning to write extensions for Blogengine.net 
SignInjector.zip (118.05 kb)