1. What Are WordPress Image Sizes?

WordPress creates several default image sizes whenever you upload a new image through the Media Library. By default, these include:

• Thumbnail: Often used for featured images in blog indexes, image galleries, or product listings.
• Medium: Ideal for displaying images within blog posts when full-resolution is not required.
• Large: Helpful for use in hero headers or as prominent on-page visuals without compromising too much on load time.
• Full (Original): The original image you uploaded, usually retained for reference or for large on-page placements.

In addition to these defaults, your active theme or certain plugins might register custom image sizes. For instance, a photography theme might introduce an extra-wide version for hero sliders, or an eCommerce plugin might define specific product image dimensions. All these variations are stored on your server, typically increasing disk space usage.