Newspapers and the day-old bread store.

Although not as common now, a generation ago the day-old bread store was a common merchant in many communities. As the name implies these stores sold the bread that bakeries had gathered from the shelves of supermarkets when the "day-old" bread was replaced with freshly baked loaves. The day-old bread stores sold these older loaves at a discount to salvage some value out this old inventory.
News photos are like bread. The value drops as they age. But not because they soon grow blue-green hairs but because the emotional connection to them wanes quickly.

Daily uploading insures the most possible sales and prevents the photojournalism version of blue-green hairs.