diff -u b/modules/image/image.field.inc b/modules/image/image.field.inc
--- b/modules/image/image.field.inc
+++ b/modules/image/image.field.inc
@@ -404,7 +404,7 @@
     '#default_value' => isset($item['alt']) ? $item['alt'] : '',
     '#description' => t('This text will be used by screen readers, search engines, or when the image cannot be loaded.'),
     // @see http://www.gawds.org/show.php?contentid=28
-    '#maxlength' => 128,
+    '#maxlength' => 512,
     '#weight' => -2,
     '#access' => (bool) $item['fid'] && $settings['alt_field'],
   );
@@ -413,7 +413,7 @@
     '#title' => t('Title'),
     '#default_value' => isset($item['title']) ? $item['title'] : '',
     '#description' => t('The title is used as a tool tip when the user hovers the mouse over the image.'),
-    '#maxlength' => 128,
+    '#maxlength' => 1024,
     '#weight' => -1,
     '#access' => (bool) $item['fid'] && $settings['title_field'],
   );
diff -u b/modules/image/image.install b/modules/image/image.install
--- b/modules/image/image.install
+++ b/modules/image/image.install
@@ -121,13 +121,13 @@
       'alt' => array(
         'description' => "Alternative image text, for the image's 'alt' attribute.",
         'type' => 'varchar',
-        'length' => 128,
+        'length' => 512,
         'not null' => FALSE,
       ),
       'title' => array(
         'description' => "Image title text, for the image's 'title' attribute.",
         'type' => 'varchar',
-        'length' => 128,
+        'length' => 1024,
         'not null' => FALSE,
       ),
       'width' => array(
@@ -395,6 +395,44 @@
 }
 
 /**
+ * Use a large setting (512 and 1024 characters) for the length of the image alt
+ * and title fields.
+ */
+function image_update_7004() {
+  $alt_spec = array(
+    'type' => 'varchar',
+    'length' => 512,
+    'not null' => FALSE,
+  );
+  $title_spec = array(
+    'type' => 'varchar',
+    'length' => 1024,
+    'not null' => FALSE,
+  );
+  $fields = _update_7000_field_read_fields(array(
+    'module' => 'image',
+    'storage_type' => 'field_sql_storage',
+  ));
+  foreach ($fields as $field_name => $field) {
+    if ($field['deleted']) {
+      $table = "field_deleted_data_{$field['id']}";
+      $revision_table = "field_deleted_revision_{$field['id']}";
+    }
+    else {
+      $table = "field_data_{$field['field_name']}";
+      $revision_table = "field_revision_{$field['field_name']}";
+    }
+    $alt_column = $field['field_name'] . '_' . 'alt';
+    db_change_field($table, $alt_column, $alt_column, $alt_spec);
+    db_change_field($revision_table, $alt_column, $alt_column, $alt_spec);
+
+    $title_column = $field['field_name'] . '_' . 'title';
+    db_change_field($table, $title_column, $title_column, $title_spec);
+    db_change_field($revision_table, $title_column, $title_column, $title_spec);
+  }
+}
+
+/**
  * Implements hook_requirements() to check the PHP GD Library.
  *
  * @param $phase
diff -u b/modules/image/image.test b/modules/image/image.test
--- b/modules/image/image.test
+++ b/modules/image/image.test
@@ -789,7 +789,6 @@
 
     // Verify that alt/title longer than allowed results in a validation error.
     $test_size = 2000;
-    $max_size = 128;
     $edit = array(
       $field_name . '[' . LANGUAGE_NONE . '][0][alt]' => $this->randomName($test_size),
       $field_name . '[' . LANGUAGE_NONE . '][0][title]' => $this->randomName($test_size),
@@ -797,11 +796,11 @@
     $this->drupalPost('node/' . $nid . '/edit', $edit, t('Save'));
     $this->assertRaw(t('Alternate text cannot be longer than %max characters but is currently %length characters long.', array(
       '%max' => $max_size,
-      '%length' => $test_size,
+      '%length' => 512,
     )));
     $this->assertRaw(t('Title cannot be longer than %max characters but is currently %length characters long.', array(
       '%max' => $max_size,
-      '%length' => $test_size,
+      '%length' => 1024,
     )));
   }