There are several ways to share images.
Share link send by mail
Copy share link
A shared project is ideal for collaboration in a professional environment. Here you decide exactly which permissions your customer should have.
E.g. he may download images or not. You can set this very granular.
The sharing settings can be assigned differently per generated share. That means you can create a link with full access for a colleague working on the project and create a "view only" link for the client.
To change the sharing settings on a shared link, go to shares.
Click on Edit in the 3 point menu. Then the familiar Share dialog opens, where you can make the desired adjustments.