Identify the Image Size: First, identify the specific image size(s) you want to exclude. WordPress image sizes are typically defined in your theme’s functions.php file using add_image_size(). Use jetpack_photon_skip_image Filter: Jetpack provides a filter jetpack_photon_skip_image which allows you to control whether an image should be served by the Site Accelerator or not. You can use this filter to check the image size and decide whether to exclude it. function wpb_exclude_specific_image_size_from_photon($skip, $image_url, $args) { // Check if the specific image size is in the URL if (strpos($image_url, '-custom-size.jpg') !== false) { // Replace '-custom-size.jpg' with your image size identifier return true; // Skip this image size from Photon } return $skip; } add_filter('jetpack_photon_skip_image', 'wpb_exclude_specific_image_size_from_photon', 10, 3); If you need to see the different size images in your site use this code: function wpb_get_image_sizes( $image_id ) { $sizes = get_intermediate_image_sizes(); $images = array(); foreach ( $sizes as $size ) { $image = wp_get_attachment_image_src( $image_id, $size ); $images[$size] = array( 'url' => $image[0], 'width' => $image[1], 'height' => $image[2] ); } return $images; } You can also find the image sizes your site offers by going to the media library: Media Library List View: Go to your WordPress dashboard. Navigate to Media > Library. Switch to the 'List View' (if you are in the 'Grid View'). Click on an image to open its 'Attachment Details' screen. Here, you can see the dimensions of the original uploaded image. However, this view does not typically show the dimensions of all different image sizes that WordPress generates. You can also ftp into your site and go to your uploads folder, then into a folder with the year, then month, etc. Once you are there it shows the files that were uploaded with the sizes. You can get your information there as well.