70-update_background_image: Check whether background image exists

On minicom server, for instance, the default LE background image is not used

Signed-off-by: Diego Pasqualin <dpasqualin@c3sl.ufpr.br>

scripts/70-update_background_image

@@ -66,8 +66,10 @@ case "$MIRROR" in
 esac
 
 for IMAGE in $IMAGES; do
-    convert -font helvetica -fill "#f3f2ed" -pointsize 200 -gravity center \
-        -draw "rotate 335 text 0,0 '$DISTNAME $RELEASE'" $IMAGE $IMAGE
+    if [ -f $IMAGE ]; then
+        convert -font helvetica -fill "#f3f2ed" -pointsize 200 -gravity center \
+                -draw "rotate 335 text 0,0 '$DISTNAME $RELEASE'" $IMAGE $IMAGE
+    fi
 done
 
 exit 0