To save it as a bitmap, you can use the following methods:
/// <summary>
/// Export the current diagram to file as a BMP image.
/// </summary>
procedure ExportAsBMP(const fileName : String; exportSize : TExportSize = esCentered);
/// <summary>
/// Export the current diagram to file as a PNG image.
/// </summary>
{$IFDEF DELPHI2009_LVL}
procedure ExportAsPNG(const fileName : String; exportSize : TExportSize = esCentered);
{$ENDIF}
/// <summary>
/// Export the current diagram to a stream as a BMP image.
/// </summary>
procedure ExportAsBMPStream(AStream: TStream; exportSize : TExportSize = esCentered);
To save to database, you can save/load to a stream and then save the stream content in a database blob:
/// <summary>
/// Save current diagram the stream specified by AStream.
/// </summary>
procedure SaveToStream(AStream: TStream; TextFormat: boolean = false); virtual;
/// <summary>
/// Load diagram from the stream specified by AStream.
/// </summary>
procedure LoadFromStream(AStream: TStream; TextFormat: boolean = false); virtual;