Provisioning always requires resources from somewhere. The resources are packages in remote repositories, compressed files from Internet addresses, and they have all kinds of sizes and formats. Depending on where they are and the available bandwidth, the download process can last longer than expected. If provisioning is a repetitive task, like in automated tests, you might want to use baked images, in order to save time.
Baked images are previously prepared with software and configuration. For this reason, they are usually bigger than the ones used in fried provisioning. In order to maintain a baked images repository, storage is really a point of consideration, mainly if the images are versioned. Downloading and uploading baked images has also its cost, so it’s better to minimize it as much as possible.