How to make sure you don’t delete referenced images in Photos for macOS<article>
<section class="page">
<p>With images and videos that you want to index, note, modify, and manage, Photos for macOS has a powerful option that lets you store that media in its original locations, rather than copied into the Photos Library. In Photos > Preferences, in the General tab, simply uncheck Copy Items to the Photos Library.</p><p>Any media that’s
referenced instead of copied will appear with a special confusing little icon that looks like an arrow pointing outside of a rectangle.</p><figure class="large "><img src="
https://images.idgesg.net/images/article/2018/06/mac911-smart-album-with-only-ref-images-100762037-large.jpg" border="0" alt="mac911 smart album with only ref images" width="700" height="516" data-imageid="100762037" data-license="IDG"/> <small class="credit">IDG</small>
<figcaption>
<p>A tiny icon on referenced images indicates they’re not copied into the Photos library.</p><p class="jumpTag"><a href="/article/3284185/photography/how-to-make-sure-you-dont-delete-referenced-images-in-photos-for-macos.html#jump">To read this article in full, please click here[/url]</p></section></article>
Source:
How to make sure you don’t delete referenced images in Photos for macOS