<div id="answerPlaceHolder"></div>
<script>
    var placeHolder = $('#answerPlaceHolder');
    var url = 'https://api.vk.com/method/wall.get?owner_id=-78812318&count=20&filter=all&v=5.45';
    var answer;
    $.ajax ({
        url:url,
        type:'get',
        crossDomain:true,
        dataType:'jsonp',
        success:function(response) {
            answer = response;
            var counter = 1;
            answer.response.items.forEach(function(item) {
                // console.log('Пост № ' + counter);
                if ((item.text != 'undefined') && (item.text != '')) {
                    placeHolder.append('<div class="blog-header">' + item.text + '</div>');
                    //console.log(item.text);
                }
                // console.log(item);
                if ((typeof(item.attachments) != = 'undefined') &&
                        (item.attachments[0].type == 'photo') &&
                        (typeof(item.attachments[0].photo.photo_604) != = 'undefined')) {
                    placeHolder.append(
                            '<img width="560px;" src="' + item.attachments[0].photo.photo_604 + '"> <div class="blog-share"><a href="http://gamer-by-life.com/share/?title=' + item.text + '&img=' + item.attachments[0].photo.photo_604 + '&time=' + item.date + '"><img src="share.png"></a></div>'
                    );
                    // console.log(item.attachments[0].photo.photo_604);
                }
                counter++;
                console.log('******************************n');
                placeHolder.append('<br>');
            });
        },
        error:
        function(error)
        {
            console.log('Ошибка');
            console.log(error);
        }
    });
</script>

<div class="blog-header">Тут текст (когда он есть) </div><img width="560px;" src="картинка"><br>

<div class="post"><div class="blog-header">Тут текст (когда он есть) </div><img width="560px;" src="картинка"><br></div>

//...
answer.response.items.forEach(function(item) {
    // console.log('Пост № ' + counter);
     var post = $("<div class='post'>");
     placeHolder.append(post);
     if ((item.text != 'undefined') && (item.text != '')) {
       post.append('<div class="blog-header">' + item.text + '</div>');
       //console.log(item.text);
     }
     // console.log(item);
     if ((typeof(item.attachments) !== 'undefined') &&
         (item.attachments[0].type == 'photo') &&
         (typeof(item.attachments[0].photo.photo_604) !== 'undefined')) {
        post.append('<img width="560px;" src="' + item.attachments[0].photo.photo_604 + '"> <div class="blog-share"><a href="http://gamer-by-life.com/share/?title=' + item.text + '&img=' + item.attachments[0].photo.photo_604 + '&time=' + item.date + '"><img src="share.png"></a></div>');
         // console.log(item.attachments[0].photo.photo_604);
     }
     counter++;
     console.log('******************************n');
     post.append('<br>');
});
//...

placeHolder.append('<div class="post"><div class="blog-header">' + item.text + '</div></div>');