Here you can take a look at site seals provided by Comodo Certification Authority for sites secured by their certificates. Please click on the site seal to get to the page with instructions on how to add it to your website.
For all other Comodo certificates, it is possible to implement different site seals depending on the certificate type and the picture you would like to use:
The information about Comodo TrustLogo and Corner of Trust for InstantSSL or PremiumSSL certificates is available in the article provided here.