Install-Package Hei.Captcha

/// <summary>
/// 泡泡中文验证码 
/// </summary>
/// <returns></returns>
public IActionResult BubbleCode()
{
    var code = _securityCode.GetRandomCnText(2);
    var imgbyte = _securityCode.GetBubbleCodeByte(code);

    return File(imgbyte, "image/png");
}

/// <summary>
/// 数字字母组合验证码
/// </summary>
/// <returns></returns>
public IActionResult HybridCode()
{
    var code = _securityCode.GetRandomEnDigitalText(4);
    var imgbyte = _securityCode.GetEnDigitalCodeByte(code);

    return File(imgbyte, "image/png");
}