It is possible to add a picture in your ManyContacts "overlays" and "full-screens".
Step 1: Go to your App setting's page:
Step 2: Host your image on the web. You can host is on your server but you can also use a third party service like tipypict.
Then edit the Text field in your ManyContacts App settings and inject the following HTML code:
-> change "http://i65.tinypic.com/xqcoiq.jpg" with the URL of your picture.