$('.tech').append("<img src='/upload/" + data['name'] + "' class='" + data['id'] + " toimg'><p class='psize'></p></div>");
$('.psize').append($('.' + data['id']).get(0).naturalWidth);

$('#container').imagesLoaded()
.always(function (instance) {
    console.log('all images loaded');
    ---- код сюда -----
});

$('.tech').append("<div class='imgwrap'><img src='/upload/" + data['name'] + "' class='" + data['id'] + " toimg'></div><p class='psize'></p>");

$('.' + data['id']).on('load', function(){
    $('.psize').append($(this).get(0).naturalWidth);
});