Problem when displaying image with other extensions

I have a small problem with this code and it is as follows:

public function leermanga($manganombre,$espacio_id,$numero='1')
{
    View::template('leermanga');
    $espacio = new Espacios();
    $espacio = $espacio->find_first($espacio_id);
    if($numero=='1')
    {
        $espacio->lecturas += 1;
        $espacio->update();
    }
    $this->espacio = $espacio;
    $scanlation = new Scanlations();
    $this->scanlation = $scanlation->find_first($espacio->scanlations_id);
    $manga = new Mangas();
    $manga = $manga->find_first($espacio->mangas_id);
    if($numero=='1')
    {
        $manga->lecturas += 1;
        $manga->update();
    }
    $this->manga = $manga;
    $capitulo = new Capitulosmanga();
    $capitulo = $capitulo->find_first($espacio->capitulosmanga_id);
    if($numero=='1')
    {
        $capitulo->lecturas += 1;
        $capitulo->update();
        if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
            $ip = $_SERVER['HTTP_CLIENT_IP'];
        } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
        } else {
            $ip = $_SERVER['REMOTE_ADDR'];
        }
        $capitulolecturas = new Capitulolecturas();
        if(!$capitulolecturas->exists("ip='".$ip."' and capitulosmanga_id=$capitulo->id and fecha='".date('Y-m-d')."'"))
        {
            $capitulolecturas->capitulosmanga_id = $capitulo->id;
            $capitulolecturas->usuarios_id = Auth::get('id');
            $capitulolecturas->ip = $ip;
            $capitulolecturas->fecha = date('Y-m-d');
            $capitulolecturas->save();
        }
    }
    $this->capitulo = $capitulo;
    $this->link= $espacio->link;
    $capitulosmanga = $capitulo->find("conditions: mangas_id=$manga->id","order: numero desc");
    $capimanga = [];
    foreach($capitulosmanga as $capi):
        $capimanga[$capi->numero] = "Capitulo $capi->numero";
    endforeach;
    $this->capimanga = $capimanga;
    $paginas = new Paginas();
    $imagen = $numero.'.jpg';
    $this->pagina = $paginas->find_first("conditions: espacios_id=$espacio->id and pagina like '%$imagen%'");
    $this->numeroanterior = $numero-1;
    $this->numero = $numero;
    $this->numerosiguiente = $numero+1;
    $this->numerofinal = $paginas->count("conditions: espacios_id=$espacio->id");
    $pagimanga = [];
    for($i=1;$i<=$this->numerofinal;$i++):
        $pagimanga[$i] = "Pagina $i";
    endfor;
    $this->pagimanga = $pagimanga;
}

This function makes it show an image, with jpg extension, but when you add an image with png or jpeg extension, it does not show it, every time I modify this:

$ image = $ number. '. jpg';

Leave the page blank.