This is Chief Red Cloud. Looking for an appraisal. I'd also like to identify the signature at the bottom right.
I cannot make out the signature on the bottom of the image. It's a painting, not a photograph, right?
It does look like this picture at the top of a webpage about Chief Red Cloud (Mapíya Lúta) of the Lakota tribe. My guess is that someone was using that photo or a similar one as a model for the artwork.
Here is another similar photograph that could also have been used. The distinctive chest plate is the same in all three images as is the single feather headdress. Many other images of Chief Red Cloud show a more ceremonial headdress full of feathers.
I would recommend looking on the back of the artwork to see if there are any other markings. Without more information, I would probably take it to an art appraiser to get their expert opinion on the value.
I would take it to an art dealer. Even if you have to pay, you will know if you have something valuable.
Your photo is not lit up bright enough near the signature to be able to try making it out. It does look like other paintings and photos of Chief Red Cloud that I've seen.
Go to Google and put in "How to get a painting appraised" It will bring up a site saying " How much is your object worth -- Researching your Art. " Click on it and it will give you sites to bring up. Then it is up to you to put in all the information you have to find an answer !!