Colane from Sioux City IA asks:
How do I add an image to my signature in Gmail?
Thanks for the question, Colane. Actually, there are a couple methods for adding an image to a Gmail signature. You can either automatically attach an image enhanced signature to all your emails, or you can prepare several different signatures and add them to individual emails.
Both methods begin in Mail settings.
Adding automatic signatures to all emails:
Under the gear icon in the upper right, click the Mail settings link.
Images are added to signatures in the Signature box, under the General tab. However, an image URL will be required, so you may want to find and copy that first. Select an image that has been uploaded to the web (one from your email, something from Facebook, etc.). Then, copy the URL with a selection from the right-click context menu. How this is done varies between browsers.
In Firefox, select Copy Image Location. Below, I’ve selected my Gmail profile picture.
In Chrome, select Copy image URL.
This method, in both Firefox and Chrome, copies the URL automatically, but in Internet Explorer, it will need to be copied manually.
Select Properties from the IE context menu and copy the URL from the Properties dialog box (see below).
Once the URL is copied, scroll down to Signature in Mail settings, type any text you’d like included in the signature, and click the Insert Image icon on the toolbar.
The Add an Image dialog box will appear. In the Image URL field, paste the copied URL and the image should appear. Click OK.
Scroll down, click Save Changes, and your new signature will appear on all future emails.
Adding different signatures to selected emails:
Once again, begin in Mail settings. Under the Labs tab, in the Search for a tab: field, type Inserting Images, and click the Enable radio button in the Inserting Images lab.
For the second step, use the same process, except this time, search for Canned Responses and enable that.
Then, click the Compose mail button…
…to create an image enhanced signature. This process is very similar to the one described above. Type the signature text and click the Insert Image icon. This time, in the Add an Image dialog box, images can also be uploaded from your computer. Just click the Browse button, select an image, and click OK.
Save the email as a Canned Response and create as many of these as you’d like to use as signatures. The article, Canned Responses  examines this feature in more detail.
Whichever method is chosen, the image size can easily be adjusted by grabbing the handles (little boxes) in the corners and pushing or pulling them to the desired size (see below).
For more on customizing email signatures, see the articles, Adding an Image to Your Windows Live Hotmail Signature  and WiseStamp. 
I hope this answers your question Colane.