一种较为简便的方法
首先建立一个脚本文件
WORKDIR=~/tmp/gdm-login-background
GST=/usr/share/gnome-shell/gnome-shell-theme.gresource
GSTRES=$(basename $GST)
mkdir -p $WORKDIR
cd $WORKDIR
mkdir theme
for r in `gresource list $GST`; do
gresource extract $GST $r >$WORKDIR$(echo $r | sed -e 's/^\/org\/gnome\/shell\//\//g')
done
cd theme
cp "$IMAGE" ./
echo "
#lockDialogGroup {
background: #2e3436 url(resource:///org/gnome/shell/theme/$(basename $IMAGE));
background-size: cover;
background-repeat: no-repeat;
}" >>gnome-shell.css
echo '<?xml version="1.0" encoding="UTF-8"?>
<gresources>
<gresource prefix="/org/gnome/shell/theme">' >"${GSTRES}.xml"
for r in `ls *.*`; do
echo " <file>$r</file>" >>"${GSTRES}.xml"
done
echo ' </gresource>
</gresources>' >>"${GSTRES}.xml"
glib-compile-resources "${GSTRES}.xml"
sudo mv "/usr/share/gnome-shell/$GSTRES" "/usr/share/gnome-shell/${GSTRES}.backup"
sudo mv "$GSTRES" /usr/share/gnome-shell/
rm -r $WORKDIR
if [ "$CREATED_TMP" = "1" ]; then
rm -r ~/tmp
fi
将这个文件命名为login-background.sh
然后确定好要设置的图片的路径，
（假设图片的路径是~/Bat.jpg）
在脚本文件所在的路径下，执行以下命令
IMAGE=~/Bat.jpg sh login-background.sh
然后重启电脑，或者重启gnome，注意要先保存你工作状态，将软件正常关闭。
重启gnome:
service gdm restart
