Image transformation

WP Cloud can resize, crop, and transform uploaded images when they are requested. The transformed response is served and cached through WP Cloud’s Edge Cache, so the site does not need to store a separate file for every variation.

The feature is enabled by default for public WP Cloud sites and does not require Jetpack. It applies to images under wp-content/uploads/.

Use transformation parameters

Append supported Site Accelerator parameters to an uploaded image URL. Common examples include:

• ?x=200 resizes the image to an exact width of 200 pixels.
• ?fit=300,300 fits the image within a 300-by-300-pixel box while preserving its aspect ratio.
• ?resize=400,220 resizes and crops the image to exactly 400 by 220 pixels.

Multiple parameters can be combined on one URL. See the Site Accelerator API documentation for the complete parameter reference.

Transformation parameters work only with image files in the site’s uploads directory. A site using the wp_uploads privacy model cannot use them because the transformed asset would otherwise bypass the site’s logged-in access requirement.

Reduce image download size

Serve images at dimensions appropriate for their display area and the end user’s device. Smaller image responses load faster and require less bandwidth. For example, resizing a 28 MB original can produce a 200 KB response that downloads in about 100 milliseconds instead of approximately 20 seconds, depending on the connection.

Do not serve a 5000-by-3000-pixel image when the page displays it in a 500-by-300-pixel area. Add transformation parameters that produce a suitable display size instead.

Native mobile applications should apply the same principle. When an API response contains the original image URL, add the required transformation parameters in the application so the end user downloads an appropriately sized image rather than the full original.

Jetpack Site Accelerator

Jetpack’s Site Accelerator image and static-file features are not required on WP Cloud. WP Cloud provides its own image transformation and Edge Cache from the site’s domain. Enabling Jetpack Site Accelerator instead loads those assets from *.wp.com, adding an external request path.

This means a theme or plugin can request a suitable image size without first writing that exact transformed copy into the site’s uploads directory.