if [ ! -d "$HOME/Pictures/Wall" ]; then
    exit 1
fi

while IFS= read -r file; do
    # Add space between filenames if string is not empty
    if [ -n "$files_string" ]; then
        files_string+=" "
    fi
    files_string+="$file"
done < <(find "$HOME/Pictures/Wall" -type f)

echo $files_string

feh --bg-fill $files_string

compton &