When adding a large gallery of images to a page for the first time, there will be a delay as concrete5 generates thumbnails and optional mobile optimized images if "generate mobile optimized images is activated.
If generate mobile optmized images is set to "on" concrete5 will create optimized images for 3 additional screen resolutions. 4 total images are created per image added.
This insures that images load quickly from each device they are viewed from.
Photo Swipe comes with built in CDN functionality for CDN services that provide you with a URL.
Simply enable the CDN option by setting it to "true" and enter the URL for your CDN.
Setting "Disable CDN checking" to "true" will disable checking your CDN for images and speed up page load time.