1.) How did you find out the time? --> use GetTickCount() in windows.h.
2.) then show me the exact code which you profiled with the profiled output --> see the code below.

main.cpp
Code:
#include <iostream>
#include <windows.h>
#include <iostream>
#include "cBild.h"

const int DIM1 = 768;
const int DIM2 = 1024;

int main()
{
    DWORD zeit1=GetTickCount(); 
    cBild data;
    std::vector <cBild> Vector;
    int i;

    DWORD zeit2; 
    for (i=0;i<5;i++)
    {
        zeit2 = GetTickCount(); 
        Vector.push_back(data);
        std::cout << "\ttime: " << (double)(GetTickCount()-zeit2)/1000 << "s" << std::endl; 
    }

    return 0;
}
cBild.h
Code:
#include <iostream>
#include <ctime>
#include <vector>

#pragma once

extern const int DIM1;
extern const int DIM2;

class cPixel
{
public:
    cPixel(void)
    {
        for (int i=0;i<3;i++)
            itsRGB[i] = 0;
    }
    void SetRGB (int type, int val)
    {itsRGB[type] = val;}
    int GetRGB (int type) const
    {return itsRGB[type];}

private:
    int itsRGB[3]; //Red,Green,Blue
};

class cBild
{
public:
    cBild(void)
    {
        itsVal = new cPixel *[DIM1];
        for (int i=0;i<DIM1;i++)
              itsVal[i] = new cPixel [DIM2];
    }
    ~cBild(void)
    {
        for (int i=0;i<DIM1;i++)
              delete[] itsVal[i];
        delete[] itsVal;
    }
    cBild (const cBild &right);
    const cBild& operator=(const cBild &right);
private:
    cPixel **itsVal;
};