Put a regular <IMG> tag on your HTML page with the SRC attribute pointing to an ASP script, e.g.
<IMG SRC="GetImage.asp?id=4">
The GetImage.asp script may look like this:
<%
Set db = Server.CreateObject("ADODB.Connection")
db.Open "data"
Set rs =db.Execute("SELECT BigBlob FROM Blobs where id = " & Request("id") )
Response.ContentType = "image/jpeg" '(or "image/gif")

This is where I get lost. What is Content Disposition and how am I to know the Content Length? Can you explain this to me?

' let the browser know the file name
Response.AddHeader "Content-Disposition", "filename=yourfile.ext"
' let the browser know the file size
Response.AddHeader "Content-Length", "545645"
Response.BinaryWrite rs("BigBlob")
%>