The New Bedford Public Library offers a link to the Digital Commonwealth online image collection that focuses on the part of Bristol Co, MA that includes New Bedford, Westport, Fairhaven, and Acushnet. One of the images is that of a GAR post but there are also other group and individual photos and rotogravure images (from old newspapers) that may give you a glimpse of your soldier. Maybe he was a policeman or fireman after the war, or played for a sports team. Many of the group images name the people in them. I plan to mine it but don't wait for me - check it out yourself.
I ran across two interesting sites recently that might be of help to anyone looking for photos, ideas, or genealogy clues. One was Yale University's Cushing/Whitney Medical Library's Digitized Collections, "Civil War Photographs" section. It contains 103 images taken during and immediately after the war by Reed B. Bontecoe, who recorded the outcome of treatments for various wounds. Most identify the specific soldier, his unit, his service record, the nature of the wound, and the medical outcome. These were ordinary soldiers who might not otherwise have had their pictures taken, and the image quality is good. Only a few are closeups of actual wounds; most are of the "whole soldier." I did find a Mayflower descendant for my Mayflower Faces site but have not finished reading all the write-ups for some link to the 3rd MA Heavy Artillery specifically. The second site was "Civil War Medicine (and Writing)" on blogspot. While I did not see anything specifically about the 3rd MA HA, the blogger covers a variety of topics not usually addressed on other sites, including home remedies, postwar employment, care of African American soldiers, Civil War museums and lots more. I ran across it when researching a sister of a New Hampshire physician living in the South for my Mayflower Faces site. The blog archives includes links to abstracts of 3 modern-day journal articles written about the Bontecoe photos and their place in medical history. In all aspects of genealogy, when you cast a wide net as to resources you are more likely to find some hidden treasure.