var array_p = new Array();
array_p['ovr_1'] = new Array('img/pic2.jpg','img/pic1.jpg');
array_p['ovr_2'] = new Array('img/pic4.jpg','img/pic3.jpg');
array_p['ovr_3'] = new Array('img/pic6.jpg','img/pic5.jpg');
array_p['ovr_4'] = new Array('img/pic8.jpg','img/pic7.jpg');
array_p['ovr_5'] = new Array('img/pic10.jpg','img/pic9.jpg');

array_p['ovr_1_s'] = new Array('img/pic1.jpg','img/pic2.jpg');
array_p['ovr_2_s'] = new Array('img/pic3.jpg','img/pic4.jpg');
array_p['ovr_3_s'] = new Array('img/pic5.jpg','img/pic6.jpg');
array_p['ovr_4_s'] = new Array('img/pic7.jpg','img/pic8.jpg');
array_p['ovr_5_s'] = new Array('img/pic9.jpg','img/pic10.jpg');
//...
function ChPicture(name_id,over_m){
    var dvd = document.getElementById(name_id);
    if(over_m){
        dvd.style.background = 'url('+array_p[name_id][1]+') top left no-repeat';
    }else{
        dvd.style.background = 'url('+array_p[name_id][0]+') top left no-repeat';
    }
}