To upload products via a template in an XLS file or via API, you need to get direct links to your images.
Direct links are links that end in .jpe, .jpeg,. jpg, or .png. For example, in the code below the direct link is highlighted in red:

How to get a direct link #
Don’t upload images to Yandex.Disk, Google Drive, or Dropbox. You can’t get a direct link on these sites.
You can get direct links to images on photo hosting sites, such as ImgBB.com. A photo hosting site is a service which anyone can use to place and store their images. Each image uploaded to such a site gets a unique URL, which can be easily shared with other users.