Сохранить изображения в новом формате

struct bmp{
int width,height;
int *mas=new int[height*width]
};

int a;
a=Image1->Picture->Bitmap->Canvas->pixel[x][y]

TBitmap->Assign(TJPGImage); // (схема)

switch (format)
{
case jpeg:....
case ico:..
case bmp:...
}

class TForm1
               : public TForm
{
__published: // IDE-managed Components
    TOpenDialog *dlg_open;
    void __fastcall FormClick( TObject *Sender );
 
private: // User declarations
public:  // User declarations
    void __fastcall act_on_bmp( String s ) {ShowMessage( "act_on_bmp method, s = " + s );}
    void __fastcall act_on_jpg( String s ) {ShowMessage( "act_on_jpg method, s = " + s );}
    void __fastcall act_on_png( String s ) {ShowMessage( "act_on_png method, s = " + s );}
 
    __fastcall TForm1( TComponent *Owner );
    __fastcall ~TForm1( );
};

#include <map>
typedef void __fastcall( __closure * act_on_ext_fptr )( String );
std::map <String, act_on_ext_fptr> ext_reference;
// ---------------------------------------------------------------------------
__fastcall TForm1::TForm1( TComponent *Owner )
               : TForm( Owner )
{
    ext_reference[".bmp"] = &act_on_bmp;
    ext_reference[".jpg"] = &act_on_jpg;
    ext_reference[".jpeg"] = &act_on_jpg;
    ext_reference[".png"] = &act_on_png;
}
// ---------------------------------------------------------------------------
void __fastcall TForm1::FormClick( TObject *Sender )
{
    if ( dlg_open->Execute( ) ) {
        String ext = ExtractFileExt( dlg_open->FileName ).LowerCase( );
        ext_reference[ext]( ext );
    }
}