var show = 5;
var current = 1;

function next(total) {
    if(current + show - 1 < total) {
        current++;
    }
    change(total);
}

function prev(total) {
    if(current > 1) {
        current--;
    }
    change(total);
}

function change(total) {
    for(i=1;i<total+1;i++) {
        document.getElementById('thumb_' + i).style.display = "none";    
    }
    for(i=1;i<total+1;i++) {
        if(i >= current && i < current + show) {
            document.getElementById('thumb_' + i).style.display = "inline";        
        }
    }
}

function show_full(source) {
    document.getElementById('full').src = source;
    document.getElementById('fulllink').href = source;
}