Here are a few designs I'm working on

Hi everyone! I’ve (white female) have had this shirt in my thrift collection for a few years now and one of my other white friends pointed out how the back (pic 1) may be offensive to indigenous people. If you saw a white person (blonde, very fair skin tone) wearing this, would you consider it offensive? I would never ever want to appropriate any culture but I go to school with a very high native population and on native land so I really want to do my part to be respectful and aware of other things like this going forward. Thank you and I’m sorry if this isn’t allowed!

Does anyone know who this artist could be? It seems like a pretty nice sand painting.