.bg-bottom          --> background-position: bottom;

.bg-center          --> background-position: center;

.bg-left            --> background-position: left;

.bg-left-bottom     --> background-position: left bottom;

.bg-left-top        --> background-position: left top;

.bg-right           --> background-position: right;

.bg-right-bottom    --> background-position: right bottom;

.bg-right-top       --> background-position: right top;

.bg-top             --> background-position: top;