Missing photos

[deeva]

Just upgraded to a12 from s8 half of my photos have vanished.  How do I find them 

[Kimmy2]

Where did you have them backed up to?

[Ventor]

@deeva ,Hello, log into One Drive from your device.You may have logged out.
2.Check the Trash if you have accidentally deleted them.
3.In Gallery / Albums Settings, check that they are not hidden.

[AndrewL]

@deeva: If you still have your S8 then I recommend using Smart Switch to transfer your photos over to the A12. 

https://www.samsung.com/uk/support/switching/

If you have registered the same Google account to your A12 I'd also recommend connecting to Wi-Fi and swiping up from your Home Screen > Google (folder) > Photos, as you should find an archive of your images stored here.