I got the solution. I used the following script: WordPress Media Manager 3.5 – default link to
and altered it to my needs with this modification:
(function() {
var _AttachmentDisplay = wp.media.view.Settings.AttachmentDisplay;
wp.media.view.Settings.AttachmentDisplay = _AttachmentDisplay.extend({
render: function() {
_AttachmentDisplay.prototype.render.apply(this, arguments);
this.$el.find('select.link-to').val('none');
this.model.set('link', 'none');
this.updateLinkTo();
this.$el.find('select.link-to').parent('label').hide();
this.$el.find('select.size option[value=full]').hide();
this.model.set('size', 'medium');
this.updateLinkTo();
}
});
})();