Hello pokergina,
Let's start off by checking the helpful steps in this article which can help with this issue: Manage your iCloud storage. Follow this guidance to delete photos on your Mac:
"Delete photos in iCloud Photos
iCloud Photos uses your iCloud storage to keep all of your photos and videos up to date across your devices. You can make more space in iCloud when you delete photos and videos that you no longer need from the Photos app on any of your devices.
Before you delete anything, make sure that you back up the photos and videos that you still want. When you use iCloud Photos and delete a photo or video on one device, it's also deleted on all other devices where you're signed in with the same Apple ID.
Use the steps below to delete photos and videos from your iCloud Photos. If you don't use iCloud Photos, you can delete photos from your Camera Roll instead.
If you are part of an iCloud Shared Photo Library, photos added to the Shared Library only count towards the storage of the person who created the Shared Library. To delete items that count towards your iCloud storage, make sure that you're viewing your Personal Library.
iCloud.com
- From your iPhone, iPad, or computer, sign in to iCloud.com.
- Select the Photos app.
- Select the photos or videos that you want to delete.
- To select multiple photos or videos, tap Select on iOS or iPadOS, or press and hold Command on a Mac or Control on a PC while you select the items.
- To select all, press and hold Command-A on macOS or Control-A on Windows, or tap Select All on iOS or iPadOS.
Tap Delete, then tap Delete."
Make sure that your folders are completely emptied by following these steps. Then, you will be able to delete the folders themselves. You can't do so until they are empty.
Let us know if we can help with anything else at all or if this doesn't settle your issue so we can look into this further with you. Thanks and have a fabulous day!