Since WordPress 2.6, WordPress has built in support for caption shortcode, which will automatically convert images, videos and other media embedded inside the code to have descriptive caption with framed border. Beside, when blogger or writer uploads and inserts (or pastes) an image by using WordPress Media Uploader, the [caption] and [caption] HTML short code is also automatically inserted.
For WordPress user or blogger who doesn’t want or doesn’t like the caption feature, WordPress developers have added a CAPTIONS_OFF constant into WordPress version 2.6. However, the constant has already been removed and no longer work. Instead, a filter hook called DISABLE_CAPTIONS has been added into WordPress 2.6.1 and all subsequent versions that allows user to disable image, picture, graphic, photo, video and other media captioning via plugin.
Caption Disabler is a WordPress plugin that removes and disables captions feature in WordPress so that all caption shortcode is not been parsed or translated, and no [caption] and [caption] HTML entities are automatically added while editing or writing.
Extract caption-disabler.php from the ZIP archive, and then upload the plug-in to the WordPress /wp-content/plugins/ directory. Activate the plugin to disable captions support in WordPress.
Just deactivate the Caption Disabler plugin will do the trick.
Caption Disabler only works on WordPress v2.6.1 or above. For WordPress 2.6, use the following trick to disable captions.