i3lock.1: --raw: add an example of how to use convert(1)

i3lock.1

@@ -81,7 +81,24 @@ as <width>x<height>:<pixfmt>. The supported pixel formats are:
 The "native" pixel format expects a pixel as a 32-bit (4-byte) integer in
 the machine's native endianness, with the upper 8 bits unused. Red, green and blue are stored in
 the remaining bits, in that order.
-Example: \-\-raw=1920x1080:rgb
+
+.BR Example:
+.Vb 6
+\&	--raw=1920x1080:rgb
+.Ve
+
+.BR
+You can use ImageMagick’s
+.IR convert(1)
+program to feed raw images into i3lock:
+
+.BR
+.Vb 6
+\&	convert wallpaper.jpg RGB:- | i3lock --raw 3840x2160:rgb --image /dev/stdin
+.Ve
+
+This allows you to load a variety of image formats without i3lock having to
+support each one explicitly.
 
 .TP
 .BI \-c\  rrggbb \fR,\ \fB\-\-color= rrggbb
@@ -147,6 +164,9 @@ The \-I (-\-inactivity-timeout=seconds) was removed because it only makes sense
 .IR xautolock(1)
 \- use i3lock as your screen saver
 
+.IR convert(1)
+\- feed a wide variety of image formats to i3lock
+
 .SH AUTHOR
 Michael Stapelberg <michael+i3lock at stapelberg dot de>