Attachments (Media files) (category)
| get_attached_file() | Retrieve attached file path based on attachment ID. |
| get_attached_media() | Retrieves media attached to the passed post. |
| get_attachment_link() | Retrieves the permalink for an attachment. |
| get_children() | Retrieve all children (attachments, revisions, or sub-pages) of the post parent ID. It works similar to get_posts(). |
| get_post_mime_type() | Retrieve the mime type of an attachment based on the ID. |
| is_local_attachment() | Check if the attachment URI is local one and is really an attachment. |
| the_attachment_link() | Display an attachment page link using an image or icon. |
| wp_attachment_is() | Verifies an attachment is of a given type. |
| wp_delete_attachment() | Trash or delete an attachment. |
| wp_get_attachment_link() | Gets a link to the attachment file or WP attachment page. Returns the <a> tag. |
| wp_get_attachment_url() | Retrieve the URL for an attachment. |
| wp_get_original_image_path() | Retrieves the path to an uploaded image file. |
| wp_get_original_image_url() | Retrieve the URL to an original attachment image. |
| wp_insert_attachment() | Insert an attachment. |
Thumbnails
| add_image_size() | Registers a new image size (thumbnail). |
| delete_post_thumbnail() | Remove a post thumbnail. |
| get_intermediate_image_sizes() | Gets the available intermediate image sizes. |
| get_post_thumbnail_id() | Gets the ID of the current (or specified) post thumbnail (featured image). Gets ID of WP attachment (image). |
| get_the_post_thumbnail() | Gets the IMG tag of the post thumbnail (if exists). |
| get_the_post_thumbnail_caption() | Gets the post thumbnail caption (description). |
| get_the_post_thumbnail_url() | Gets the thumbnail URL specified for the post. If there is no post thumbnail, it returns false. |
| has_image_size() | Check if an image size exists. |
| has_post_thumbnail() | Check if post has an image attached. |
| image_get_intermediate_size() | Retrieves the image's intermediate size (resized) path, width, and height. |
| remove_image_size() | Removes a previously registered image size by it name. The new image size is registered with add_image_size(). |
| set_post_thumbnail() | Set a post thumbnail. |
| set_post_thumbnail_size() | Registers an image size for the post thumbnail. |
| the_post_thumbnail() | Display the post thumbnail. |
| the_post_thumbnail_caption() | Displays the post thumbnail caption. |
| the_post_thumbnail_url() | Display the post thumbnail URL. |
| wp_get_additional_image_sizes() | Gets data of all additionally registered image sizes (thumbnails). |
| wp_get_attachment_thumb_url() | Retrieve URL for an attachment thumbnail. |
| wp_get_image_editor() | Returns a WP_Image_Editor instance and loads file into it. |
| wp_get_registered_image_subsizes() | Returns a normalized list of all currently registered image sub-sizes. |
Rarely used
| attachment_url_to_postid() | Tries to convert an attachment URL into a post ID. |
| get_allowed_mime_types() | Retrieve list of allowed mime types and file extensions. |
| wp_get_audio_extensions() | Returns a filtered list of WP-supported audio formats. |
| wp_get_ext_types() | Retrieves the list of common file extensions and their types. |
| wp_get_video_extensions() | Returns a filtered list of WP-supported video formats. |
| wp_getimagesize() | Allows PHP's getimagesize() to be debuggable when necessary. |
| wp_read_image_metadata() | Get extended image metadata, exif or iptc as available. |
Metadata (postmeta)
| delete_post_meta_by_key() | Deletes everything from post meta matching the given meta key. |
| wp_generate_attachment_metadata() | Generate post thumbnail attachment meta data. |
| wp_get_attachment_metadata() | Retrieve attachment meta field for attachment ID. |
| wp_maybe_generate_attachment_metadata() | Maybe attempts to generate attachment metadata, if missing. |
| wp_read_audio_metadata() | Retrieve metadata from a audio file's ID3 tags |
| wp_update_attachment_metadata() | Update metadata for an attachment. |
Images
| file_is_displayable_image() | Validate that file is suitable for displaying within a web page. |
| image_downsize() | Scale an image to fit a particular size (such as 'thumb' or 'medium'). |
| next_image_link() | Displays next image link that has the same post parent. |
| previous_image_link() | Displays previous image link that has the same post parent. |
| wp_attachment_is_image() | Determines whether the specified post is WordPress attachment image. A conditional tag. |
| wp_get_attachment_caption() | Retrieves the caption of specified attachment. |
| wp_get_attachment_image() | Get an HTML img element representing an image attachment |
| wp_get_attachment_image_sizes() | Retrieves the value for an image attachment's 'sizes' attribute. |
| wp_get_attachment_image_src() | Gets an array of data for the specified image: URL, width, height of the attachment image. |
| wp_get_attachment_image_srcset() | Retrieves the value for an image attachment's 'srcset' attribute. |
| wp_get_attachment_image_url() | Get the URL of an image attachment. |
| wp_get_image_mime() | Gets the real MIME type of an image file. |
Gallery
| get_post_galleries() | Retrieves galleries from the passed post's content. |
| get_post_galleries_images() | Retrieve the image srcs from galleries from a post's content, if present |
| get_post_gallery() | Check a specified post's content for gallery and, if present, return the first |
| get_post_gallery_images() | Retrieves an array of image URLs that belong to the first gallery of the specified post. |
Upload/Download
| media_handle_sideload() | Handles a side-loaded file in the same way as an uploaded file is handled by media_handle_upload(). |
| media_handle_upload() | Save a file submitted from a POST request and create an attachment post for it. |
| media_sideload_image() | Downloads an image from the specified URL and attaches it to a post. |
| wp_check_filetype() | Retrieve the file type from the file name. |
| wp_check_filetype_and_ext() | Attempts to determine the real file type of a file. |
| wp_get_upload_dir() | Retrieves uploads directory information. |
| wp_handle_sideload() | Wrapper for _wp_handle_upload(). |
| wp_handle_upload() | Wrapper for _wp_handle_upload(). |
| wp_max_upload_size() | Determines the maximum upload size allowed in php.ini. |
| wp_unique_filename() | Get a filename that is sanitized and unique for the given directory. |
| wp_upload_bits() | Create a file in the upload folder with given content. |
| wp_upload_dir() | Get an array containing the current upload directory's path and url. |