Then there is some problem with the wifi (or with the wifi settings on your phone). For some reason the wifi blocks the requests to upload files to your selected cloud storage. I am not able to reproduce this and I haven't heard about this problem from other users yet. What Cloud service have you selected for Cloud Sync?
I didn't fully understand your last sentence. What do you mean with "resenting"? Also what do you mean with "until I delete them and upload them without wifi on"? How do you upload deleted pictures?