Send Images over WhatsApp in C#/.NET (Visual Studio 2019) - Legacy Guide

Automate WhatsApp Image Sharing with C#/.NET and Visual Studio 2019

Looking to automate WhatsApp image sharing, visual notifications, or media delivery from your C#/.NET applications using Visual Studio 2019? This legacy guide walks you through sending images to WhatsApp users using C# with Visual Studio 2019 and the WhatsMate WA Gateway REST API. Perfect for .NET developers maintaining legacy applications or using older Visual Studio versions.

⚠️ Legacy Notice: This guide uses Visual Studio 2019 and legacy .NET libraries. For modern development with Visual Studio 2022, updated .NET features, and better performance, please use our updated Visual Studio 2022 tutorial instead.

📋 Prerequisites

Before you begin, ensure you have:

1. A WhatsMate WA Gateway account - Required for API access
2. Recipient registration - Each recipient must register with the Gateway first
3. Visual Studio 2019 - .NET development environment (or compatible IDE)
4. Image file ready - Have the image you want to send available locally
5. System.Web.Extensions reference - Required for JSON serialization in legacy .NET

⚠️ Important: Recipients must register with the WhatsMate WA Gateway before they can receive messages. Unregistered users will not receive any messages from the Gateway. Registration instructions are available on the official WhatsMate site.

📝 Step-by-Step Implementation

Follow these steps to send your first image to a WhatsApp user from a C# application using Visual Studio 2019:

1. Copy the C# Code Template

Start by copying the following source code into your C# file:

2. Configure a few Parameters

Customize these key parameters in the C# code:

• Line 10: Replace YOUR_INSTANCE_ID with your WhatsApp gateway instance ID
• Lines 11-12: Update YOUR_CLIENT_ID_HERE and YOUR_CLIENT_SECRET_HERE with your Client ID and Secret
• Line 20: Replace 12025550105 with the target phone number (including the country code)
• Line 22: Replace C:\\TEMP\\cute-girl.jpg with the path to your image file
• Line 23: Replace Lovely Gal with an optional caption for your image

3. Add Required Reference

In Visual Studio 2019, add a reference to System.Web.Extensions for JSON serialization support:

1. Right-click on References in your project
2. Select “Add Reference”
3. Find and check “System.Web.Extensions”
4. Click OK

4. Send Your Image

Build and run your C# application in Visual Studio 2019 to deliver your image to WhatsApp:

1. Press F5 to build and run in debug mode
2. Or use Ctrl+F5 to run without debugging
3. Check the console output for success confirmation

🔧 Common Use Cases

This legacy automation approach is ideal for:

• Legacy Windows applications - Send images to WhatsApp from older Windows Forms or WPF apps
• Maintenance projects - Update existing .NET applications with WhatsApp image sharing
• Backend services - Integrate WhatsApp image sharing into legacy ASP.NET web applications
• Scheduled tasks - Use Windows Task Scheduler with .NET console apps for regular image delivery
• Business applications - Add WhatsApp notifications with images to enterprise .NET solutions

🚀 Get Started Today

Ready to automate your image sharing over WhatsApp with C#/.NET and Visual Studio 2019? You’ll need a trial account to access the API. Sign up for a 2-week trial and start sending images within minutes!

Next Steps: Once you’ve mastered basic image sending, explore advanced features like sending documents or group messages through the WhatsMate WA Gateway API documentation.

💡 Upgrade Recommendation: For new projects or modern development, we strongly recommend using our Visual Studio 2022 tutorial which uses modern .NET libraries, better performance, and updated development practices.