http://artbuffer.com/
I made Artbuffer to create my own wall art without having to spend years learning to paint. I've successfully used it to create my own :-)
Some examples:
https://www.artbuffer.com/view?a=wslyHCoGjqoA3ZKgsQ_hNAlnshT...
https://www.artbuffer.com/view?a=-9Wr6aLtgF383zsAWxchXJbt8CW...
https://www.artbuffer.com/view?a=OuIs3I6vHAyqV-PoMb6EFiRVAFw...