diff --git a/extra/swayimgrc.5 b/extra/swayimgrc.5
index f516368..b76da71 100644
--- a/extra/swayimgrc.5
+++ b/extra/swayimgrc.5
@@ -70,6 +70,7 @@ Set background for transparent images:
 \fInone\fR: fully transparent, window color will be use;
 \fIgrid\fR: draw chessboard (default);
 \fI#COLOR\fR: solid RGB color in hex format, e.g `#102030`.
+\fI#COLOR\fR: RGBA color in hex format, e.g `#10203040`.
 .\" ----------------------------------------------------------------------------
 .IP "\fBposition\fR = \fI[MODE|COORDINATES]\fR"
 Set initial position of the window (Sway only):
@@ -88,6 +89,7 @@ Set initial size of the window:
 Set window background:
 \fInone\fR: transparent window (default);
 \fI#COLOR\fR: solid RGB color in hex format, e.g `#102030`.
+\fI#COLOR\fR: RGBA color in hex format, e.g `#10203040`.
 .\" ----------------------------------------------------------------------------
 .IP "\fBslideshow\fR = \fI[yes|no]\fR"
 Run slideshow at startup, \fIno\fR by default.