If you are a photographer and uploading some of your photographs to the web, you may be interested in how WordPress handles EXIF, IPTC and XMP metadata.
Metadata is information about an image, and can be included in JPEG image files.
EXIF metadata is information about the image recorded directly from the camera – for example, the exposure time and the date the photo was taken.
IPTC (and more recently XMP) metadata is information about the image from the photographer, for example, captions or copyright information.
If you are using a Mac you can see this metadata by selecting the file in the Finder and using Cmd I (Get Info). If you are using Windows you can use this excellent online tool (which can be used on images from your hard disk or from any website):
Online EXIF Viewer.
WordPress preserves EXIF information in full size images loaded to your website. It will also extract the Exif data to make it available for plugin developers (for example, if someone wanted a plugin to display Exif information in a certain way).
When WordPress uploads images, in addition to uploading the Full Size image it automatically creates several differently sized versions of the image:
- a Large version
- a Medium version
- a Thumbnail version
These different sized versions are used in different places including in your Gallery display – this displays the Thumbnails (in the scrolling list to the left) and the Large image (the single image display to the right), and clicking the Large image displays the Full Size.
The EXIF data is not carried across by WordPress from the Full Size image to the Thumbnail, Medium and Large versions of the image.