function CreateWebCamSnapshot(FilePath)
{
var Device = new ActiveXObject("WIA.DeviceManager"),
Count = Device.DeviceInfos.Count,
oDevice, Item, Image;

for (var k=1; k<=Count; k++)
    if (Device.DeviceInfos(k).Type == 3)
    {
    try
    {
        oDevice = Device.DeviceInfos(k).Connect();
        Item = oDevice.ExecuteCommand("{AF933CAC-ACAD-11D2-A093-00C04F72DC3C}");
        Image = Item.Transfer("{557CF401-1A04-11D3-9A73-0000F81EF32E}");
        Image.SaveFile(FilePath);
    }
    catch (e) {}
    }
}

CreateWebCamSnapshot("C:\\aaa.jpg");

Function CreateWebCamSnapshot(FilePath)
    Dim Device, oDevice, Count, Item, Image, k
    Set Device = CreateObject("WIA.DeviceManager")
    Count = Device.DeviceInfos.Count

    On Error Resume Next
    For k=1 To Count
        if Device.DeviceInfos(k).Type = 3 Then
            Set oDevice = Device.DeviceInfos(k).Connect
            Set Item = oDevice.ExecuteCommand("{AF933CAC-ACAD-11D2-A093-00C04F72DC3C}")
            Set Image = Item.Transfer("{557CF401-1A04-11D3-9A73-0000F81EF32E}")
            Image.SaveFile FilePath
        End if
    Next
End Function

CreateWebCamSnapshot "C:\aaa.jpg"