Preview item on this Donation NPC

[celeron0134]

how will i add the preview item on this script?

prontera,157,149,5	script	Proof of Donation#1	955,{
    mes "Your["+getitemname(.Cost)+"]["+countitem(.Cost)+"]";
    mes "^E217171 Proof of Donation = 25 PHP";
close2;
callshop "dyn_shop"+.a,1;
npcshopattach "dyn_shop"+.a;
end;
OnInit:
set .a,strnpcinfo(2);
//=========================================
set .Cost,7179;
//=========================================
setarray .buy_id[0],1228;
setarray .buy_co[0],40;
//=========================================

npcshopitem "dyn_shop1",.buy_id[0],.buy_co[0];
for(set .ik,1;.ik<getarraysize(.buy_id);set .ik,.ik+1){
    npcshopadditem "dyn_shop"+.a,.buy_id[.ik],.buy_co[.ik];
}
end;

OnBuyItem:
    getinventorylist;
    if(@bought_quantity[@i] <= 0){
        goto OnEnrd;
        end;
    }
    for(set @i,0;@i<getarraysize(@bought_nameid);set @i,@i+1){
//KeyWorld
        set [email protected], getiteminfo( @bought_nameid[[email protected]], 2 );
        if (  [email protected] == 4 || [email protected] == 5 || [email protected] == 7 || [email protected] == 8 ) 
            set [email protected], [email protected] + 1;
        else {
            for( set [email protected],0; [email protected]<@inventorylist_count; set [email protected], [email protected]+1 )
                if ( @inventorylist_id[[email protected]] == @bought_nameid[[email protected]] )
                    break;
            if ( [email protected] == @inventorylist_count )
                set [email protected], [email protected]+1 ;
        }
        for(set @i2,0;@i2<getarraysize(.buy_id);set @i2,@i2+1){
            if(@bought_nameid[@i]==.buy_id[@i2]){
                set @gh,@gh+.buy_co[@i2]*@bought_quantity[@i];
                set @wh,@wh+getiteminfo(@bought_nameid[@i],6)*@bought_quantity[@i];
            }
        }
    }
    if ( [email protected]count + @inventorylist_count > 100 ) {
        announce "[D-Shop]: Can't hold more than 100 items.",bc_self;
        goto OnEnrd;
    }
    if(countitem(.Cost)<@gh){
        announce "[D-Shop]:["+getitemname(.Cost)+"] isn't enough",bc_self;
        goto OnEnrd;
        end;
    }else{
        if(@wh>(MaxWeight-Weight)){
            announce "[D-Shop]:Too heavy",bc_self;
            goto OnEnrd;
            end;
        }else{
            delitem .Cost,@gh;
            for(set @i,0;@i<getarraysize(@bought_nameid);set @i,@i+1){
                getitem @bought_nameid[@i],@bought_quantity[@i];
            }            
        }
    }
OnEnrd:
    set @gh,0;
    set @wh,0;
    set @i,0;
    set @i2,0;
    deletearray @bought_quantity,getarraysize(@bought_quantity);
    deletearray @bought_nameid,getarraysize(@bought_nameid);
end;
}

so that there would be an option for preview and purchase the item

[BeWan]

use this one instead. 

https://github.com/rathena/rathena/blob/master/npc/custom/quests/quest_shop.txt