Drupal: filefield_sources + visual_select_file + multiupload_imagefield_widget = ❤️, see https://makeyoulivebetter.org.ua/node/625

fix_image_uploader.css

.filefield-source.filefield-source-reference {
    float: right;
    overflow: hidden;
}
.filefield-source.filefield-source-reference > .form-item {
    padding: 0;
}

fix_image_uploader.info.ini

name = Fix Image Uploader
description = This module make possible using of filefield_sources + visual_select_file + multiupload_image_widget.
core = 7.x
package = MakeYouLiveBetter

fix_image_uploader.module.php

<?php
/**
 * @file
 * fix_image_uploader module file.
 */

/**
 * Implements hook_block_list_alter().
 *
 * Hide all blocks and drupalchat popup from visual file select pop-up.
 */
function fix_image_uploader_block_list_alter(&$blocks) {
  if (current_path() === 'admin/visual_select_file') {
    foreach ($blocks as $block) {
      if (!($block->module === 'system' && $block->delta === 'main')) {
        unset($blocks[$block->bid]);
      }
    }
  }
  elseif (module_exists('drupalchat') && function_exists('drupalchat_init')) {
    drupalchat_init();
  }
}

/**
 * Implements hook_module_implements_alter().
 *
 * Remove drupalchat init hook to prevent it run from all pages.
 */
function fix_image_uploader_module_implements_alter(&$implementations, $hook) {
  if ($hook == 'init' && module_exists('drupalchat')) {
    unset($implementations['drupalchat']);
  }
}

/**
 * Implements hook_preprocess_HOOK().
 *
 * Hide admin toolbar from visual file select pop-up.
 */
function fix_image_uploader_preprocess_html(&$variables) {
  if (current_path() === 'admin/visual_select_file' && isset($variables['page']['page_top']['toolbar'])) {
    $variables['page']['page_top']['toolbar']['#access'] = FALSE;
  }
}


/**
 * Implements hook_element_info_alter().
 *
 * Process multi-upload file widget with filefield_sources module.
 */
function fix_image_uploader_element_info_alter(&$type) {
  $type['mfw_managed_file']['#process'][] = 'filefield_sources_field_process';
  $type['mfw_managed_file']['#process'][] = 'visual_select_file_pre_render_filefield_sources_element';
  $type['mfw_managed_file']['#process'][] = 'fix_image_uploader_filefield_sources_process';
  $type['mfw_managed_file']['#pre_render'][] = 'filefield_sources_field_pre_render';
  $type['mfw_managed_file']['#element_validate'][] = 'filefield_sources_field_validate';
  $type['mfw_managed_file']['#file_value_callbacks'][] = 'filefield_sources_field_value';
}

/**
 * Implements hook_filefield_sources_widgets().
 */
function fix_image_uploader_filefield_sources_widgets() {
  return array('image_miw');
}

/**
 * A #process callback to extend the filefield_widget element type.
 */
function fix_image_uploader_filefield_sources_process($element) {
  // Hide filefield_sources tabs.
  if (isset($element['filefield_sources_list'])) {
    $element['filefield_sources_list']['#access'] = FALSE;
  }

  $element['#attached']['css'][] = drupal_get_path('module', 'fix_image_uploader') . '/fix_image_uploader.css';

  return $element;
}