I can't tell the difference. On Wix picture, it stiill looks okay to me. What do you mean by "getting ugly"?
Is your site live? If so, can you share the site address so I can view it? Some smaller screens can only take a header width of 800Px.
If your pic looks good in PS and other picture viewers and it does not look good on the website, I would tend to call it HTML/CSS issue. I can look into it if you provide the site address.