Can I delete some pictures from my IPad and keep the pictures in the icloud

iCloud Photos is a syncing service. Any photo you delete from a device where iCloud Photos is turned on will also be deleted from iCloud and from any other device connected to iCloud Photos. You can potentially reduce the storage space required on a device by turning on Optimize Storage. See: https://support.apple.com/en-us/HT204264

Apple does not currently offer cloud-only storage for photos. If that is what you want or need, you may want to explore 3rd party options such as Google Photos or Dropbox.

Another way that photos may be on iCloud (if you don’t have iCloud Photos turned on) is via a backup of an iOS device. The only thing you can do with a backup is use it to restore a device or set up a new device. The contents of backups are not viewable at iCloud.com and if you delete a photo from a device it will not be included in future backups and will be lost.

Welcome, AngelPi58, to Apple Support Communities!

While using photos or videos through the Photos App, you cannot place photos or videos on iCloud (such as iCloud Photos) without at least having a lower quality version on at least one of your iCloud associated devices.

Using iCloud directly through a browser, however, there may be a way, though I haven’t tested it, yet.

As FoxFifth points out, there are third party cloud storage options, as well.