Programmatically upload image to Episerver

The first part is getting the image stream which can be written into an Episerver blob.

private async Task<Stream> GetImageStreamAsync(string url)
{
    var stream = new MemoryStream();

    try
    {
        var client = new HttpClient();
        var response = await client.GetAsync(url);
        response.EnsureSuccessStatusCode();

        var responseStream = await response.Content.ReadAsStreamAsync();

        var img = Image.FromStream(responseStream);

        var encoder = GetEncoder(img.RawFormat);
        var encoderParameters = GetEncoderParameters();

        img.Save(stream, encoder, encoderParameters);

        stream.Seek(0, SeekOrigin.Begin);
    }
    catch (Exception)
    {
        stream = null;
    }

    return stream;
}

private static EncoderParameters GetEncoderParameters()
{
    var qualityEncoder = Encoder.Quality;
    var encoderParameters = new EncoderParameters(1);
    var qualityEncoderParameter = new EncoderParameter(qualityEncoder, 100L);
    encoderParameters.Param[0] = qualityEncoderParameter;
    return encoderParameters;
}

private ImageCodecInfo GetEncoder(ImageFormat format)
{
    return ImageCodecInfo
        .GetImageDecoders()
        .FirstOrDefault(codec => codec.FormatID == format.Guid);
}

Here I am using an HttpClient to download the image by URL. Then I am creating an image stream from the response stream using an Image class. It requires image encoder and its parameters. An image encoder can be loaded by its GUID from the ImageCodecInfo.GetImageDecoders(). ImageFormat is specific for the different type of images - JPEGs, PNGs, etc. The Image.FromStream method detects the image's format from the response stream and sets it on the RawFormat field. You can use this field to get image extension.

Once you get the stream, create a new image data file, create a blob, write the stream data into the blob and save the image data.

public async Task<ContentReference> UploadImage(string url, string imageName, ContentReference folderLink)
{
    var imageFile = _contentRepository.GetDefault<ImageFile>(folderLink);
    imageFile.Name = imageName;
    using (var stream = await GetImageStreamAsync(url))
    {
        if (stream == null) return null;

        var blob = _blobFactory.CreateBlob(imageFile.BinaryDataContainer, Path.GetExtension(imageFile.Name));
        blob.Write(stream);
        imageFile.BinaryData = blob;
        return _contentRepository.Save(imageFile, SaveAction.Publish, AccessLevel.NoAccess);
    }
}

In this example, the ImageFile class is image's data file which inherits from the ImageData. This contains all your image's meta-data. Use IBlobFactory.CreateBlob to create a new blob for the image and use Write method to write content to it. The blob is associated with the image data by BinaryData property on the image data class. Finally, store the image data using IContentRepository.Save method.