Thank you for submitting your item for appraisal. This is a later print of the iconic phantom punch photo showing Liston and Ali. The felt pen signature might be authentic but the certificate is dubious. There is no verifiable name and address on the certificate. There might have been a Franmart Tripleplay company been active in New Jersey in the 1990s, but that is about all that can be said. Sports memorabilia as an investment have lost credibility during the past few years. Buyers are much more aware of fakes. You would need another certificate by a reputable service like PSA. I am not saying they always get it right, but this would be the only solution for you.
Decorative photos like this with a felt pen signature similar to the above sell in the price range as mentioned at auction.