This is valuable information which will help you to manage your pictures and categorize them afterwards. If you have a large collection of pictures that includes descriptions, you have a real asset. What I do after I come back from a trip or a photo shoot session is first adding information about the picture to the picture (this is also called metadata). The more detailed is your picture informati
on, the better it is. So what I am doing, is to look over the internet about information about the item. For example, if I am taking a picture of a church at a specific location, I will have a look about it on the internet. I will compile all the information and write a short summary about it and add into the picture. I always care to have included in the describtion, information like: location (country, city location) subject describtion and try to add a short anectdote about it. You can have a look at my photo collection in fb to have an idea about picture descriptions