This happened to me last week and I am confident in saying there is no way to recover it.
I too lost my photos on internal storage on the S8+
Phone updated to oreo, woke up the next morning and ALL my photos were gone. (DCIM folder)
I'm a 3rd Line Engineer so you can be assured I've tried everything and there is no way to recover them without a backup.
I started by using the recovery apps (Recuva, es file manager, disk digger, photo recovery)
Tried looking at all the files, checking all my backups, looking for NOMEDIA, looking for LOSTDIR, I have no SD card so all internal.
All this doesn't work, and for it to dig deeper into internal memory, the phone has to be rooted. (using TWRP & Odin)
You also can't root until you erase internal memory. So you are basically stuck in a vicious cycle.
I even rooted the device eventually, used ADB tools to try to unencrypt the data file and see if I could find my files, but Samsung has a unique code on all devices stopping you from getting in. I spent 2 straight days on this.
There is no way around this, I am shocked, but also feel like it's my fault for not having a backup.... then again with iCloud, it just automatically backed up so how can it be...
Thinking of it, after reading everyone's comments, I feel that I am at ease as I have only lost a couple of holiday photos (had this phone for a month) as opposed to special memories.
The phone is now sold and I got myself a proper phone, iPhone XS Max.
I am never getting another android phone again.
I bought Samsung Galaxy S8 two months back and today all my gallery pictures dissapeared.Can you please help ?
I have the latest the OS version and cleared all my cache. I lost almost 1000 pictures.
I had an S8 Samsung phone and I took some pictures but I can't get them back up now