VB.NET

Convert Inline Data-URL Images to Related Parts

Demonstrates the Chilkat Email.ConvertInlineImages method, which converts images embedded inline within HTML (as base64 data URLs) into multipart/related MIME parts referenced from the HTML by cid:. This example sets an HTML body containing a data-URL image and converts it.

Background: HTML can embed an image two ways: as a data: URL (the base64 bytes sit right in the src attribute) or as a related part referenced by cid:. Many email clients don't render data: URLs for security reasons, so converting them to proper multipart/related parts — the traditional email way to embed images — greatly improves how reliably the images display.

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VB.NET

Dim success As Boolean = False

'  Demonstrates the ConvertInlineImages method, which converts images embedded inline within
'  HTML (as base64 data URLs) into multipart/related MIME parts referenced from the HTML by
'  CID.

Dim email As New Chilkat.Email
email.Subject = "Convert inline images"

'  An HTML body with a base64 data-URL image (a 1x1 PNG).
email.SetHtmlBody("<html><body><img src=""data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==""/></body></html>")

Debug.WriteLine("NumRelatedItems before = " & email.NumRelatedItems)

'  Convert the inline data-URL image(s) to multipart/related parts referenced by CID.

success = email.ConvertInlineImages()
If (success = False) Then
    Debug.WriteLine(email.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("NumRelatedItems after = " & email.NumRelatedItems)