Can I delete pictures from iPhone without worrying about deleting photos from MAC

Hi s-nyc,

This depends entirely on whether or not you're using iCloud Photo Library. If you are, then removing photos via your iPhone will remove those photos from iCloud and, thus, your Mac. However, if you are using iCloud Photo Library, you can enable Optimize iPhone Storage in Settings -> iCloud -> Photos in order to allow for additional photos to be taken so long as there's room in your iCloud Storage.

iCloud Photo Library automatically keeps all your photos and videos in the original, high-resolution version. Follow these steps to choose how you store your photos and videos on your device:

• In iOS, tap Settings > iCloud > Photos or Settings > Photos & Camera, then select a storage setting.
• In OS X, click Photos > Preferences > iCloud, then select a storage setting.

If you turn on Optimize [device] Storage, iCloud Photo Library will automatically manage the size of your library on your device, so you can make the most of your device's storage and access more photos than ever. All of your original, full-resolution photos and videos are stored in iCloud while device-size versions are kept on your device. You can download the original photos and videos over Wi-Fi or cellular when you need them.

iCloud Photo Library FAQ
https://support.apple.com/en-us/HT204264

However, if you're not using iCloud Photo Library, then removing photos from your iPhone will NOT affect what photos are stored on your Mac.

All my best,

Allen