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Editorial Team
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Asked: 2026-05-24T17:26:07+00:00

I’ve found some similar questions on SO and elsewhere, but nothing that quite does

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I’ve found some similar questions on SO and elsewhere, but nothing that quite does what I’m looking for (or, maybe I’m just too boneheaded to connect the dots!)

I’m looking to return a thumbnail image from a full size image stored as varbinary(max) in the database. I’ll be using the thumbnails in a gallery-style view, so small size / efficient loading is crucial. I’ve been using an .ashx to return the full size image into a bound asp.net Image control, with the following code:

Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest

    Dim conn As New SqlConnection()
    conn.ConnectionString = *connectionstring*

    Dim cmd As New SqlCommand()
    cmd.Connection = conn
    cmd.CommandType = CommandType.StoredProcedure
    cmd.CommandText = "GetEmplHeadShot"

    Dim emplID As New SqlParameter("@emplID", context.Request.QueryString("emplid"))
    cmd.Parameters.Add(emplID)

    conn.Open()

    Dim myReader As SqlDataReader = cmd.ExecuteReader
    If myReader.Read Then

        context.Response.BinaryWrite(myReader("HeadShot"))
        context.Response.ContentType = "image/jpeg"

    End If
    myReader.Close()
    conn.Close()

End Sub

I realize it’s probably best to address the re-size at the upload, and stored the smaller image as a discrete column. But in the meantime, is it possible to program the handler to re-size the image on the fly? Ideally, I’d be able to pass an additional query string parameter, something like isResized from the image binding, allowing the same handler to be used for both full size and re-sized images.

Any advice / assistance would be greatly appreciated. Ideas on alternative approaches (i.e. “you’re going about this all wrong”) would also be very welcome.

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1 Answer

  1. Editorial Team

    Yes, instead of returning the var binary directly back to the response, put it into a Bitmap object (via a memory stream created from the varbinary)

    Resize the BMP, then save it back to the memory stream via the save method, then output the memory stream back to a byte array to the response.

    Keep in mind though that instantiating a Bitmap on the server can be very memory intesive. If you have multiple requests simultaneously, you could run into “out of memory exceptions”. It’s probably a good idea to save the thumbnails to db or disk when created, so that you don’t have to keep re-creating them on every request.

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