Why do my pictures keep coming back after I deleted them?

Having the same exact problem. It's not making sense really. My phone tells me I'm running low on storag space & that I need to delete something to free up space in order for all applications to operate properly. Seeing as how my photos take up the most space (nothing else is above a gig other than snapchat) I decide to mass delete my photos. But the freaking phone is so full of storage, the photo app doesn't work properly making me unable to delete anything over like 2 photos at a time. It's honestly ridiculous. I've had cheaper phones work twice as well when operating on low storage space. Not once did any phone I had prior to this get so full of space that I was somehow unable to free up some space. Mainly bc that wouldn't make sense. Like, I'm literally being told to free up some space so my phone can operate normally but bc my phone isn't operating normally, I can't free up space. It's a conundru. how do I go about freeing up space when the best option to free up space freezes my phone and cancels out whatever it is I'm doing? & the iCloud thing doesn't apply to me. Don't even have an account set up. Honesty getting sick of this. Went through this literally just last week. Deleted 2,000 photos just to have them appear right back in my photos. I finally, after who knows how long, deleted about 1,000 of the ones that returned somehow only to have the 1.4 gb of free space I had vanish in a couple of updates & downloads. Now I'm back to square one. Whatever this problem is, it needs to be fixed. There's no reason a $600 phone should be messing up with something as simple as deleting photos to free up space.

My suggestion is to not use iCPL. Find a computer that works, import them to the computer and then copy them from the computer to an external hard drive or large flash drive. Alternatively upload them to Dropbox or Flickr.

The exact same thing happened to me to and while everyone is saying to iCloud them unfortunately I have a computer that I think could crash any minute I now only have three apps on my phone and most of them are glitchimg a lot ! I am at the stage where I am having to consider buying a new phone, even though apart from the storage everything is working out perfectly fine ! It is a big problem and I don't know what to do about it . Does anyone have any suggestions?

iCloud Photo Library is syncing your picture back automatically. Disable it, delete the pictures from iCloud and they will be gone if that is what you want.

iCloud Photo Library FAQ - Apple Support