In Delphi, there is a component called TScrollBox, which allows you to add a scrollbar to a TImage component.
I need to add a scrollbar to
Yes, Win32 defines a scroll bar class, documented here: https://msdn.microsoft.com/en-us/library/windows/desktop/bb787529.aspx
The Windows API provides two types of scrollbars:
One is the standalone Scroll Bar control, that comes with its own window handle.
The other is attached to a window that has the WS_HSCROLL and/or WS_VSCROLL Window Styles. The latter is a nonclient scrollbar and not a control. Consequently it doesn't have a window handle. To manipulate a nonclient scrollbar, pass the window handle of the containing window together with the SB_HORZ or SB_VERT as the nBar parameter to the appropriate scrollbar functions.