Can anyone help me identify the person in the attached photo. Possible surname is "Garriga", possible Spanish American Civil War?
It would help to see the subject's badge in closer detail. It looks to be a GAR (Grand Army of the Republic) badge. In that case, he would be a veteran of the American Civil War. Example of the badge can be seen here: https://www.digitalcommonwealth.org/search/commonwealth:z029pz361
I would suggest investigating the history of photographs as well, to date when the actual print of the photograph could have been made. It is interesting that there is no photographer's imprint, and that the photograph is not correctly sized to fit the card backing. It would lead to believe that it was not a professional print.
Do you recognize the building in the background? Do you have any idea where this picture was taken? It is clearly a posed shot, but one that is simple enough that it could be done by inexperienced photographers (hence the imperfect formatting of the photograph and card) I'm wondering if he was visiting a war memorial and had his picture taken. Or possibly a recognition for Civil War veterans and they had a photographer there for everyone who wanted a picture.
If you can find that building, you may be able to find out if there was an event which this person may have attended. Often a local newspaper would cover such an event and might even list all the names of attendees.