How to publish image to endpoint with asp net web api

Hello, I am trying to publish an image through an endpoint and for that I need to receive a parameter. The method works fine but as long as you don't send a . in the path eg: api/images/GetImagenLink/xxxxx

But if I put a dot to specify the format eg: api/images/GetImagenLink/xxxxx.jpg then it crashes and gives an error.

How can I receive something like image.png as a parameter in the URL????

[System.Web.Http.Route("api/imagenes/GetImagenLink/{articulo}")]
    // GET: api/Imagenes
    public async Task<HttpResponseMessage> GetImagenLink(string articulo)
    {
        HttpResponseMessage result = new HttpResponseMessage();

        try
        {

            noef.controllers.selects consulta = new noef.controllers.selects();

            noef.models.Conexion conexion = new noef.models.Conexion
            {
                Servidor = "xxxxxx",
                BD = "xxxxx",
                Usuario = "xxx",
                Password = "xxx"
            };

            string[] split = articulo.Split('.');

            List<object> objetos = await consulta.SelectFromDatabase(conexion, $"SELECT  [ARTICULO],[FOTO],[ARCHIVO] FROM xxxxx where ARTICULO = '{split[0]}'");




 var serial = JsonConvert.SerializeObject(objetos, Formatting.Indented);

            var desereal = JsonConvert.DeserializeObject<List<Respuesta>>(serial);

            var source = desereal.Where(x => x.Columna.ToString() == "FOTO").FirstOrDefault();



            var array = source.Valor;

            result.Content = new ByteArrayContent(Convert.FromBase64String(array.ToString()));

            result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/split[1]");


            result.StatusCode = HttpStatusCode.OK;

            return result;

        }
        catch (Exception d)
        {

            result.StatusCode = HttpStatusCode.BadRequest;

            return result;
        }

    }