Definitions of the core WordPress media concepts, Mediapapa features, image formats and compression techniques that matter for managing and maintaining a healthy media library.
WordPress Core
Media Library
The built-in WordPress tool for uploading, storing and organising all files on your site.
Attachment
A media file uploaded to WordPress, stored as a special post type in the database.
Attachment ID
The unique numeric identifier WordPress assigns to every uploaded file.
Featured Image
The primary image associated with a post or page, stored as a postmeta reference.
Unattached Media
Files with no parent post — not the same as unused media.
Metadata
Alt text, title, caption and description — the four editable fields on every media file.
Alt Text
The accessibility description read by screen readers and used by search engines.
Caption
Visible text displayed below or beside an image on the front end.
MIME Type
File type identifier used by WordPress to validate uploads and filter the library.
Image Thumbnails
Automatically generated smaller versions of images for different layout contexts.
Responsive Images
Images that adapt to screen size and resolution using srcset and sizes attributes.
srcset
HTML attribute that provides browsers with a list of image variants to choose from.
Upload Directory
The server folder where WordPress stores uploaded files, organised by year and month.
Attachment Page
Auto-generated WordPress page for each uploaded file. Most sites should disable these.
Mediapapa Features
Library Health
The overall health score for your entire media library, from 0 to 100.
Media Score
Per-file health rating based on compression, metadata and format.
Usage Index
Complete map of where every file is referenced across your entire site.
Deletion Warnings
Alerts that block deletion of files still referenced in content.
Safe Replace
Updates every file reference sitewide before replacing or removing a file.
Duplicate Detection
Identifies identical files by content hash and groups them for safe removal.
Media Tagging
Assign multiple tags to files for flexible organisation beyond folder structures.
Unused Media
Files with zero references across all posts, pages, fields and theme options.
Pre-publish Checks
Editor alerts that flag media issues before a post goes live.
AI Metadata Generation
AI-drafted alt text, title and caption based on image content analysis.
Formats & Compression
WebP
Modern format offering 25–35% better compression than JPEG at equivalent quality.
AVIF
Next-generation format achieving 30–50% better compression than JPEG.
JPEG
The standard format for photographs. Lossy compression. The baseline to replace with WebP.
PNG
Lossless format with transparency support. Best for logos, icons and screenshots.
GIF
Animated image format natively supported by WordPress. Large file sizes compared to WebP animation.
SVG
Vector format for logos and icons. Not allowed by default in WordPress without a plugin.
Document format stored in the Media Library as an attachment. Not compressed by Mediapapa.
Lossy Compression
Reduces file size by discarding imperceptible image data. Typically 40–70% smaller.
Lossless Compression
Reduces file size without discarding any data. Original can be perfectly reconstructed.
Image Optimisation
Reducing file size through compression, format conversion and resizing without visible quality loss.
Concepts
Duplicate Images
Identical files uploaded more than once, creating multiple attachment IDs for the same content.
EXIF Data
Technical metadata embedded in image files: camera, date, GPS. Stripped by default during compression.
Image SEO
Optimising images for search visibility through alt text, compression and modern formats.
Bulk Operations
Actions applied to multiple files at once — compress, tag, delete, replace.
Media Governance
The ongoing practice of keeping a media library healthy over time — not just a one-time cleanup.
Media Library Audit
Systematic review of all files to identify unused files, duplicates, missing metadata and compression gaps.
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