What format are the files in? You will likely have to convert them to a bitmap (easiest to work with development wise) then convert them back to their original type (probably jpeg or something compressed for web use). Without knowing the filetype you don't know the file headers (important) or the actual structure of the image data.
Post the code that shows how you are getting the data from the DB. Bitmap has a few static members that allow you to build one from a file, a stream, or another image. We'll need to figuire out the best way to construct it for you.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...