You can easily add a MotionMail timer into Gmail through the Insert Photo Button.

Using the Insert Photo Tool in Gmail

1. Login to Gmail
   
   
2. Click Compose
   
   
3. Click on the 'Insert Photo' link on the bottom of the editor
   
   
   
4. In the Web Address (URL) field paste only the URL of the timer. This is the part starting with http: as seen below.  ONLY include the URL as seen in the image below. 
5. You will see a preview of the timer below the URL you entered
   

6. Click the Insert button
   
   

7. Continue composing your email