This is not an html plugin, it is a VB/VBA function (with VB6 form format) that has no preview, to see it working, you need to add it to your VBA project

If you don't have an idea of what is it, then this is not for you

' Name: LoadImage
' Description:Custom function to load PNG file in a regular ImageBox in Excel/VBA.
Found here, it looks like it is working like a charm, except the background is in black.

'Usage: Set UserForm1.Image1.Picture = LoadImage("C:\Folder1\Insight.png")

Private Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(0 To 7) As Byte
End Type
Private Type PICTDESC
Size As Long
Type As Long
hPic As Long
hPal As Long
End Type
Private Type GdiplusStartupInput
GdiplusVersion As Long
DebugEventCallback As Long
SuppressBackgroundThread As Long
SuppressExternalCodecs As Long
End Type
Private Declare Function GdiplusStartup Lib "GDIPlus" (token As Long, _
inputbuf As GdiplusStartupInput, Optional ByVal outputbuf As Long = 0) As Long
Private Declare Function GdipCreateBitmapFromFile Lib "GDIPlus" (ByVal FileName As Long, bitmap As Long) As Long
Private Declare Function GdipCreateHBITMAPFromBitmap Lib "GDIPlus" (ByVal bitmap As Long, hbmReturn As Long, _
ByVal background As Long) As Long
Private Declare Function GdipDisposeImage Lib "GDIPlus" (ByVal Image As Long) As Long
Private Declare Function GdiplusShutdown Lib "GDIPlus" (ByVal token As Long) As Long
Private Declare Function OleCreatePictureIndirect Lib "olepro32.dll" (PicDesc As PICTDESC, _
RefIID As GUID, ByVal fPictureOwnsHandle As Long, IPic As IPicture) As Long

Public Function LoadImage(ByVal strFName As String) As IPicture
Dim uGdiInput As GdiplusStartupInput
Dim hGdiPlus As Long
Dim hGdiImage As Long
Dim hBitmap As Long
uGdiInput.GdiplusVersion = 1
If GdiplusStartup(hGdiPlus, uGdiInput) = 0 Then
If GdipCreateBitmapFromFile(StrPtr(strFName), hGdiImage) = 0 Then
GdipCreateHBITMAPFromBitmap hGdiImage, hBitmap, 0
Set LoadImage = ConvertToIPicture(hBitmap)
GdipDisposeImage hGdiImage
End If
GdiplusShutdown hGdiPlus
End If
End Function
Public Function ConvertToIPicture(ByVal hPic As Long) As IPicture
Dim uPicInfo As PICTDESC
Dim IID_IDispatch As GUID
Dim IPic As IPicture

With IID_IDispatch
.Data1 = &H7BF80980
.Data2 = &HBF32
.Data3 = &H101A
.Data4(0) = &H8B
.Data4(1) = &HBB
.Data4(2) = &H0
.Data4(3) = &HAA
.Data4(4) = &H0
.Data4(5) = &H30
.Data4(6) = &HC
.Data4(7) = &HAB
End With
With uPicInfo
.Size = Len(uPicInfo)
.hPic = hPic
.hPal = 0
End With
OleCreatePictureIndirect uPicInfo, IID_IDispatch, True, IPic
Set ConvertToIPicture = IPic
End Function