Iphone Backup size dropping
I used to backup my iphone 6 every week. It was taking considerable time to get backed up and the size of the backup was around 15 GB. More than 80% of content is coming from pictures and photos in my iphone.
I dont remember whether I have made any modification, howver I noticed the last backup took less than 20 minutes and the size is currently around a.5 GB.
Please, any specific reason behind this? Do you know what is the content of the backup? Is it something customizable?
Thanks
iPhone 6, iOS 9.2.1