Photos on iphone 7 deleted after update
That's odd -- maybe iTunes restored a backup when you plugged it in? The "setup as new or restore from backup" screen in iTunes when you first plug in an iPhone is confusing, so maybe you chose restore from backup?

If so, we should check to see if iTunes made an "emergency" backup before restoring the old backup. Open iTunes and select Preferences from the iTunes menu (Mac) or Edit menu (Windows).

Do you see a backup listed in there from about the time that this happened, maybe with a date stamp in the name? If so, you could either try restoring that backup (a little heavy handed) or use a third party tool to go look in the contents of the backup. (I work on a tool called Decipher Backup Browser -- the free trial will let you poke around and preview all of the camera roll photos to see if you have a backup with your photos. https://deciphertools.com/decipher-backup-browser.html)