After i put my iphone pictures on my PC, can i delete all of them off my phone?

I literally just imported all my photos and videos onto my computer because i need more storage on my iphone. Now since almost all my pictures are on my PC, can i delete all my pictures in my camera roll on my phone? I really need more storage, and thats why i had to transfer all my pictures.

Yes you can delete all your pictures off of your iPhone now.

Yes you can delete the photos because the PC should save the photos.

Of course, you can delete the pictures on your Phone after you copy the pictures to computer.

I'm trying to delete all pictures but a few off of my 6plus iPhone most of them are already saved on the computer but not all. I used to be able to do this now it won't please help