I think you are asking about a custom signature. If so, this is what you do to create one:

Click on My Profile > Settings & Options > Edit Signature

Once on the Edit Signature page, type in your quote(s) in the text box. You can experiment with different fonts, their sizes, colors and text alignment. To see what your signature will look like click on the Preview Signature button.

To add an image to your signature:

Directly underneath the text box (on the same page) is the Signature Picture option. There are two ways to add an image:

1. From another website. You have to enter the URL the image is found on.
2. Upload from your computer. Note the file size and dimensions.

You can once again check your signature by previewing it. After you are satisfied, make sure to click on the Save Signature button.

I hope this helps. If you need more help, feel free to ask.