Finder not updating contents
MacOS Sierra on Macbook Pro 2012:
1. I add a photo to a folder. The photo is clearly visible in the folder.
2. From a browser I click on 'Browse' button to add the photo (to a Facebook post for example).
3. I navigate to the folder containing the photo but it is not shown there. Viewing the folder in the Finder however, the photo is there.
For some reason the folder contents are not updated immediately when accessed through a browser. It might take several hours, even a full day for the photo to appear. I have done this with Safari, Chrome and Firefox with the same results.
Does anyone have any idea what might be behind this?