I was goggling for "guitar wallpaper" and I noticed that guitar companies and web sites are using them to advertise.
example I queried for guitar wallpaper and I find it and some have
www.whatever on the pictures
and I thought this site and maybe your
planetalk site could benefit from it.
there's like over 2 million under "guitar wallpaper" but it could be narrowed down by putting it as acoustic guitar wallpaper or
slide guitar wallpaper or any other tricks you can pull out of your sleeves
anyway I did solve the mystery of the smile, see attached pic.