How do I delete photos from my old iPhone after transferring to a new one?

Hi! I just recently transferred to a new iphone. My old phone’s storage was 256GB and my (new) current phone is 128GB so i decided to delete a lot of my photos from my older phone to make some space and for easier transfer. After transferring, i decided to delete more photos on my current phone, however, my icloud hasn't finished syncing which resulted to the selected photos not being deleted on my old phone. I hope that makes sense.

Would syncing the icloud mean that the ones I deleted on my new phone would then be deleted on my old phone or would I have to manually do it too? Thanks in advance!

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