Manufacturer Picture instead of default picture

protected virtual PictureModel PrepareProductOverviewPictureModel(Product product, int? productThumbPictureSize = null)
{
    if (product == null)
        throw new ArgumentNullException(nameof(product));

    var productName = _localizationService.GetLocalized(product, x => x.Name);
    //If a size has been set in the view, we use it in priority
    var pictureSize = productThumbPictureSize ?? _mediaSettings.ProductThumbPictureSize;

    //prepare picture model
    var cacheKey = string.Format(NopModelCacheDefaults.ProductDefaultPictureModelKey,
        product.Id, pictureSize, true, _workContext.WorkingLanguage.Id, _webHelper.IsCurrentConnectionSecured(),
        _storeContext.CurrentStore.Id);

    var defaultPictureModel = _cacheManager.Get(cacheKey, () =>
    {
        var picture = _pictureService.GetPicturesByProductId(product.Id, 1).FirstOrDefault();
        if (picture == null && product.ProductManufacturers.Any())
        {
            var manufacturer = product.ProductManufacturers.FirstOrDefault();
            picture = _pictureService.GetPictureById(manufacturer.ProductId);
        }

        var pictureModel = new PictureModel
        {
            ImageUrl = _pictureService.GetPictureUrl(picture, pictureSize),
            FullSizeImageUrl = _pictureService.GetPictureUrl(picture),
            //"title" attribute
            Title = (picture != null && !string.IsNullOrEmpty(picture.TitleAttribute))
                ? picture.TitleAttribute
                : string.Format(_localizationService.GetResource("Media.Product.ImageLinkTitleFormat"),
                    productName),
            //"alt" attribute
            AlternateText = (picture != null && !string.IsNullOrEmpty(picture.AltAttribute))
                ? picture.AltAttribute
                : string.Format(_localizationService.GetResource("Media.Product.ImageAlternateTextFormat"),
                    productName)
        };

        return pictureModel;
    });

    return defaultPictureModel;
}

protected virtual PictureModel PrepareProductOverviewPictureModel(Product product, int? productThumbPictureSize = null)
{
    if (product == null)
        throw new ArgumentNullException(nameof(product));

    var productName = _localizationService.GetLocalized(product, x => x.Name);
    //If a size has been set in the view, we use it in priority
    var pictureSize = productThumbPictureSize ?? _mediaSettings.ProductThumbPictureSize;

    //prepare picture model
    var cacheKey = string.Format(NopModelCacheDefaults.ProductDefaultPictureModelKey,
        product.Id, pictureSize, true, _workContext.WorkingLanguage.Id, _webHelper.IsCurrentConnectionSecured(),
        _storeContext.CurrentStore.Id);

    var defaultPictureModel = _cacheManager.Get(cacheKey, () =>
    {
        var picture = _pictureService.GetPicturesByProductId(product.Id, 1).FirstOrDefault();
        if (picture == null && product.ProductManufacturers.Any())
        {
            var pm = product.ProductManufacturers.FirstOrDefault();
            picture = _pictureService.GetPictureById(pm.Manufacturer.PictureId);
        }
        var pictureModel = new PictureModel
        {
            ImageUrl = _pictureService.GetPictureUrl(picture, pictureSize),
            FullSizeImageUrl = _pictureService.GetPictureUrl(picture),
            //"title" attribute
            Title = (picture != null && !string.IsNullOrEmpty(picture.TitleAttribute))
                ? picture.TitleAttribute
                : string.Format(_localizationService.GetResource("Media.Product.ImageLinkTitleFormat"),
                    productName),
            //"alt" attribute
            AlternateText = (picture != null && !string.IsNullOrEmpty(picture.AltAttribute))
                ? picture.AltAttribute
                : string.Format(_localizationService.GetResource("Media.Product.ImageAlternateTextFormat"),
                    productName)
        };

        return pictureModel;
    });

    return defaultPictureModel;
}

protected virtual PictureModel PrepareProductDetailsPictureModel(Product product, bool isAssociatedProduct, out IList<PictureModel> allPictureModels)
{
    if (product == null)
        throw new ArgumentNullException(nameof(product));

    //default picture size
    var defaultPictureSize = isAssociatedProduct ?
        _mediaSettings.AssociatedProductPictureSize :
        _mediaSettings.ProductDetailsPictureSize;

    //prepare picture models
    var productPicturesCacheKey = string.Format(NopModelCacheDefaults.ProductDetailsPicturesModelKey, product.Id, defaultPictureSize, isAssociatedProduct, _workContext.WorkingLanguage.Id, _webHelper.IsCurrentConnectionSecured(), _storeContext.CurrentStore.Id);
    var cachedPictures = _cacheManager.Get(productPicturesCacheKey, () =>
    {
        var productName = _localizationService.GetLocalized(product, x => x.Name);

        var pictures = _pictureService.GetPicturesByProductId(product.Id);
        var defaultPicture = pictures.FirstOrDefault();
        if (defaultPicture == null && product.ProductManufacturers.Any())
        {
            var pm = product.ProductManufacturers.FirstOrDefault();
            defaultPicture = _pictureService.GetPictureById(pm.Manufacturer.PictureId);
        }
        var defaultPictureModel = new PictureModel
        {
            ImageUrl = _pictureService.GetPictureUrl(defaultPicture, defaultPictureSize, !isAssociatedProduct),
            FullSizeImageUrl = _pictureService.GetPictureUrl(defaultPicture, 0, !isAssociatedProduct)
        };
        //"title" attribute
        defaultPictureModel.Title = (defaultPicture != null && !string.IsNullOrEmpty(defaultPicture.TitleAttribute)) ?
            defaultPicture.TitleAttribute :
            string.Format(_localizationService.GetResource("Media.Product.ImageLinkTitleFormat.Details"), productName);
        //"alt" attribute
        defaultPictureModel.AlternateText = (defaultPicture != null && !string.IsNullOrEmpty(defaultPicture.AltAttribute)) ?
            defaultPicture.AltAttribute :
            string.Format(_localizationService.GetResource("Media.Product.ImageAlternateTextFormat.Details"), productName);

        //all pictures
        var pictureModels = new List<PictureModel>();
        foreach (var picture in pictures)
        {
            var pictureModel = new PictureModel
            {
                ImageUrl = _pictureService.GetPictureUrl(picture, defaultPictureSize, !isAssociatedProduct),
                ThumbImageUrl = _pictureService.GetPictureUrl(picture, _mediaSettings.ProductThumbPictureSizeOnProductDetailsPage),
                FullSizeImageUrl = _pictureService.GetPictureUrl(picture),
                Title = string.Format(_localizationService.GetResource("Media.Product.ImageLinkTitleFormat.Details"), productName),
                AlternateText = string.Format(_localizationService.GetResource("Media.Product.ImageAlternateTextFormat.Details"), productName),
            };
            //"title" attribute
            pictureModel.Title = !string.IsNullOrEmpty(picture.TitleAttribute) ?
                picture.TitleAttribute :
                string.Format(_localizationService.GetResource("Media.Product.ImageLinkTitleFormat.Details"), productName);
            //"alt" attribute
            pictureModel.AlternateText = !string.IsNullOrEmpty(picture.AltAttribute) ?
                picture.AltAttribute :
                string.Format(_localizationService.GetResource("Media.Product.ImageAlternateTextFormat.Details"), productName);

            pictureModels.Add(pictureModel);
        }

        return new { DefaultPictureModel = defaultPictureModel, PictureModels = pictureModels };
    });

    allPictureModels = cachedPictures.PictureModels;
    return cachedPictures.DefaultPictureModel;
}