Here are some tips on how you can pin images and products from your Wix Website using Wix Stores. One way I like to "pin" online store products is to use screenshots to capture a grouping of products that you can then pin and link to your store page. To take a screenshot on a Mac, you can use Command + Shift and the number 4 on your keyboard, this will give you crosshairs that you can then select the area of the screen you want to capture.
If you run into trouble with Pinterest not pinning a site by using "Save from Site" in the Create Pin panel, you're not alone. Wix website URLs often give the response "Site is not reachable." You are not alone, this is happening across all Wix websites, I've found. The workaround is to upload photos/screenshots and manually link them instead. See below: