Hi.,
1 ) Kindly refer this screenshot ,
* http://recordit.co/HL8oAkS2r2
* Sorry as of now we don’t have that option.
2 ) Get into Admin Panel > Appearance > Customize > Additional CSS > and paste the code , and replace the image URL as per your need.
#toTop {
background: url(http://kalvi.dttheme.com/default/wp-content/themes/kalvi/images/[email protected]) no-repeat right bottom !important;
}