unsigned int * pData = GfxImageGetData(m_pImage);

for(int y = 0 ; y < SizeY ; ++y )
{
    for(int x = 0 ; x < SizeX ; ++x)
    {
        int iIndex = x + SizeX * y;

        pData[iIndex] = GfxColor(r,g,b,a);
    }
}


GfxImageSave(m_pImage, "Level.tga");