Convert MHTML to Image in C#

To convert MHTML to image formats in C#, open the MHTML file as a stream, create ImageSaveOptions, choose the output image format, and call Converter.ConvertMHTML() with the stream, options, and output path or stream provider.

MHTML stores a web page and its resources in a single archive. MHTML to image conversion is useful for previews, thumbnails, visual archives, QA snapshots, and systems that need raster output instead of a document file.

Before running the examples, install and configure Aspose.HTML for .NET in your project. The complete C# example project is available in the Aspose.HTML for .NET GitHub repository.

Convert MHTML to JPG with Two Lines of C#

The static Converter class provides the shortest path from an MHTML stream to an image file. The example below converts MHTML to JPG with ImageSaveOptions.

// Convert MHTML to JPG in C#

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Invoke the ConvertMHTML() method to convert MHTML to JPG
Converter.ConvertMHTML(stream, new ImageSaveOptions(ImageFormat.Jpeg), Path.Combine(OutputDir, "convert-by-two-lines.jpg"));

Convert MHTML to JPG in C#

Use JPG output when you need compact previews or thumbnails and small file size matters more than transparency or lossless text edges.

The workflow is:

1. Open the MHTML file with File.OpenRead() or another readable stream.
2. Create an ImageSaveOptions instance with ImageFormat.Jpeg.
3. Call Converter.ConvertMHTML(stream, options, savePath).
4. Save the generated JPG file to the target output path.

// Convert MHTML to JPG using C#

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");
            
// Create an instance of ImageSaveOptions
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.Jpeg);

// Call the ConvertMHTML() method to convert MHTML to JPG
Converter.ConvertMHTML(stream, options, Path.Combine(OutputDir, "sample-output.jpg"));

Choose an Image Format for MHTML Output

• Use JPG for compact previews and thumbnails when file size matters.
• Use PNG for lossless output, sharp text, UI screenshots, and transparency-friendly workflows.
• Use BMP when a Windows-oriented or legacy imaging pipeline expects bitmap files.
• Use GIF for simple compatibility-focused image output, not for high-detail full-color pages.
• Use TIFF for archiving, printing, scanning, document imaging, or workflows that need TIFF compression.

Convert MHTML to PNG in C#

PNG is the default ImageSaveOptions.Format value and is often a good choice for sharp previews. The following example converts MHTML to PNG.

// Convert MHTML to PNG using C#

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Create an instance of ImageSaveOptions
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.Png);

// Call the ConvertMHTML() method to convert MHTML to PNG
Converter.ConvertMHTML(stream, options, Path.Combine(OutputDir, "sample-output.png"));

Convert MHTML to BMP in C#

BMP can be useful for Windows-oriented or legacy image workflows. The following example converts MHTML to BMP.

// Convert MHTML to BMP using C#

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Create an instance of ImageSaveOptions
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.Bmp);

// Call the ConvertMHTML() method to convert MHTML to BMP
Converter.ConvertMHTML(stream, options, Path.Combine(OutputDir, "sample-output.bmp"));

Convert MHTML to GIF in C#

GIF can be useful for simple compatibility-focused output. The following example converts MHTML to GIF.

// Convert MHTML to GIF in C#

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Create an instance of ImageSaveOptions
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.Gif);

// Call the ConvertMHTML() method to convert MHTML to GIF
Converter.ConvertMHTML(stream, options, Path.Combine(OutputDir, "sample-output.gif"));

Convert MHTML to TIFF in C#

TIFF can be useful for archival, printing, scanning, and document imaging workflows. The following example converts MHTML to TIFF.

// Convert MHTML to TIFF in C#

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Prepare a path to save the converted file 
string savePath = Path.Combine(OutputDir, "sample-options.tiff");

// Create an instance of ImageSaveOptions
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.Tiff);

// Call the ConvertMHTML() method to convert MHTML to TIFF
Converter.ConvertMHTML(stream, options, savePath);

Customize MHTML to Image with ImageSaveOptions

Use ImageSaveOptions when the generated image needs custom rendering settings.

To customize MHTML to image conversion:

1. Open the MHTML source stream.
2. Create ImageSaveOptions and choose the output format.
3. Configure only the options required by the target output, such as PageSetup, BackgroundColor, HorizontalResolution, VerticalResolution, UseAntialiasing, or TIFF Compression.
4. Pass the stream, options, and output path to Converter.ConvertMHTML().

Option	Use it to control
Format	The output image format. The default value is PNG; use ImageFormat.Jpeg, ImageFormat.Bmp, ImageFormat.Gif, or ImageFormat.Tiff when another format is required.
BackgroundColor	The color used to fill the image background. The default value is transparent.
PageSetup	Page size, margins, and page layout settings.
HorizontalResolution and VerticalResolution	Output resolution values used by the rendering process. The default value is 300 dpi for each property.
UseAntialiasing	Image rendering quality. Antialiasing is enabled by default.
Text	Text rendering configuration through TextOptions.
Compression	TIFF compression. Use it only for TIFF output; the default value is LZW.

// Convert MHTML to JPG in C# with custom settings

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Prepare a path to save the converted file
string savePath = Path.Combine(OutputDir, "sample-options.jpg");

// Initailize the ImageSaveOptions with a custom page-size and a background color
ImageSaveOptions options = new ImageSaveOptions(ImageFormat.Jpeg)
{
    PageSetup =
        {
            AnyPage = new Page()
            {
                Size = new Aspose.Html.Drawing.Size(Length.FromPixels(1000), Length.FromPixels(500))
            }
        },
    BackgroundColor = System.Drawing.Color.Beige
};

// Call the ConvertMHTML() method to convert MHTML to JPG
Converter.ConvertMHTML(stream, options, savePath);

Related Image Workflows

• How to Resize Document During Conversion from HTML?
• Set Font Folder to Render HTML
• Fine-Tuning Converters
• Rendering Options

Save MHTML to Image with an Output Stream Provider

Use ICreateStreamProvider when the conversion output should be written through streams instead of only to a file path. This is useful for memory-based workflows, remote storage, databases, and services that decide where rendered image output is stored.

// Implement a custom MemoryStream provider for advanced control over HTML rendering output streams

class MemoryStreamProvider : Aspose.Html.IO.ICreateStreamProvider
{
    // List of MemoryStream objects created during the document rendering
    public List<MemoryStream> Streams { get; } = new List<MemoryStream>();

    public Stream GetStream(string name, string extension)
    {
        // This method is called when only one output stream is required, for instance for XPS, PDF or TIFF formats
        MemoryStream result = new MemoryStream();
        Streams.Add(result);
        return result;
    }

    public Stream GetStream(string name, string extension, int page)
    {
        // This method is called when the creation of multiple output streams are required. For instance, during the rendering HTML to list of image files (JPG, PNG, etc.)
        MemoryStream result = new MemoryStream();
        Streams.Add(result);
        return result;
    }

    public void ReleaseStream(Stream stream)
    {
        // Here you can release the stream filled with data and, for instance, flush it to the hard-drive
    }

    public void Dispose()
    {
        // Releasing resources
        foreach (MemoryStream stream in Streams)
            stream.Dispose();
    }
}

The following example converts MHTML to JPG with MemoryStreamProvider.

// Convert MHTML to JPG in C# using memory stream

// Create an instance of MemoryStreamProvider
using MemoryStreamProvider streamProvider = new MemoryStreamProvider();

// Open an existing MHTML file for reading
using FileStream stream = File.OpenRead(DataDir + "sample.mht");

// Prepare a path to save the converted file
string savePath = Path.Combine(OutputDir, "stream-provider.jpg");

// Convert MHTML to JPG by using the MemoryStreamProvider class
Converter.ConvertMHTML(stream, new ImageSaveOptions(ImageFormat.Jpeg), streamProvider);

// Get access to the memory streams that contain the resulted data
for (int i = 0; i < streamProvider.Streams.Count; i++)
{
    MemoryStream memory = streamProvider.Streams[i];
    memory.Seek(0, SeekOrigin.Begin);

    // Flush the page to the output file
    using (FileStream fs = File.Create(savePath))
    {
        memory.CopyTo(fs);
    }
}

Related MHTML Conversion Guides

• Convert MHTML to PDF – render an MHTML archive as a PDF document.
• Convert MHTML to DOCX – save an MHTML archive as a Word document.
• Convert MHTML to XPS – render MHTML as fixed-layout XPS output.

Other Platforms

• MHTML Converter in Java
• MHTML Converter in Python via .NET

Try Online MHTML to Image Conversion

Use the online MHTML to JPG Converter for quick manual conversion. Use Aspose.HTML for .NET when MHTML to image conversion must run inside a C# application, service, or document pipeline.