Tak na to jak vkladat obrazek za běhu v jine proceduře jsem už přišel.

procedure TForm1.Button1Click(Sender: TObject);
begin
if a = 5 then ColorRow := 5; // pokud a = 5 nakresli obrazek do 5 řadku
StringGrid1.Repaint;
end;

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer; Rect: TRect;
State: TGridDrawState);
begin
begin
with TStringGrid(Sender) do
begin
Canvas.FillRect(Rect);
if (ACol=0) then
begin
if (ARow = ColorRow) then
ImageList1.Draw(Canvas,Rect.Left,Rect.Top,0);
end
else
Canvas.TextOut(Rect.Left+1, Rect.Top+1, Cells[ACol, ARow]);
end;
end;
end;