Image: If $image_source is set to ascii display a warning in -v

neofetch

@@ -1898,6 +1898,12 @@ get_image_backend() {
             case "$image_source" in
                 "wall"*) get_wallpaper 2>/dev/null ;;
                 "off") image_backend="off"; return ;;
+                "ascii")
+                    to_ascii "Image: \$image_source set to 'ascii', falling back to ascii mode. "
+                    err "Image: Change \$image_source to another value to use image mode."
+                    return
+                ;;
+
                 *)
                     if [[ -d "$image_source" ]]; then
                         files=("${image_source%/}"/*.{png,jpg,jpeg})