Dropbox
Dropbox is a popular cloud storage solution used by many vendors and suppliers but getting image links to work with PDX requires a few quick edits so that PDX receives the raw image rather than the Dropbox framed image.
Here's how to use Drop Box with PDX
Alternatives:
A very simple bare-bones image hosting site.
Click on the image link they provide to open the image in the browser and use that final link for PDX
Click on the file name and select 'Make Public' from the contextual menu
Select the public link option and click on it to copy the link
A GitHub guide to export to CSV: Cloudinary Export CSV List