The pricing level reflects how popular an image is. Most of the images in the database are level 0 when they are submitted (images submitted in assignments
are an exception). When someone downloads an image, the download will be added to the image's total number of downloads. When the amount of downloads per image reaches a specific number the level of the file is increased, increasing its pricing as well (the number of credits you pay for it). This pricing is affected only by the number of downloads the image had, not by how many downloads you have made using your account.