Batch lmage upload

First off give all the images you want to bulk upload an easy to find name, something besides the default file number your camera gives it. Then create a blank page in  the unlinked secton of you site, it doesn't have to be an enabled page. Add a gallery block to that page and upload all the images you care to. It can be a bulk upload if choosing the files directiy from their location on your computer or device. Those images will now appear in your assest library where you can search for them by name, newest or oldest, use them anywhere in your site, delete them singly or as a group.  You can't upload a folder of images or create one in your assest library but you can group name images which will show up in the asset seach, such as parkerwedding1.jpg, parkerwedding2,jpg etc. 

https://www.elliemakeswebsites.com/blog/squarespace-new-assets-library-feature