[Samsung Galaxy S8+ Questions & Answers] jdilirst:
Found this solution in a Samsung Forum:

"Theory behind photos date"

If you did not change the file name it should be written in a way which indicates the year, day and month as well as the precise hour and minute when it was take. This applies to all kind of photos (from every single camera, not only phone ones) and to screenshots, but does not apply to whatsapp photos since only the year, day and month is indicated in the name followed by 000xx where xx indicates in which order you received the photos sent on the same day.

Methods to fix the photo date

Both methods i will show you embed metadata files into the photo, so it will never change the date if it is moved between devices or sd cards!

Method 1:

You can, if you have windows 10 photos program in your pc look at the name of the photo and click on the 3 vertical dots at the top right hand side of the pc screen and then click on file info. The date is now shown at the left of the picture and you can permanently modify that by hand. If you have many photos to modify use method 2. Method 1 is good if you have a few photos to edit or you have to edit a video date, for the other use case go to the notes at the end.

Method 2:

The program i personally use is

EXIF date changer*

you can dowload it from the developer website here , it should work on windows XP, vista, 7, 8.1, 10. As you can see they offer a free version and a paid version, the free version allow you to fix unlimited amount of photos without having more nieche features, so it is more than enough for what you need to do, so dowload the free version unless you want to support the developer or you need the pro features.

*i want to specify that i have no affiliation with the developer and that i am suggesting their app because i use it myself and it works perfectly. there are other programs which do the same thing if you like others more you can use them.

After you have dowloaded and installed EXIF date changer on your pc move all the photos from your sd card into a folder on you desktop (you can now delete all the photos from the sd card, but i highly recommend you not to delete the desktop copy till you have verified at the end of the procedure everything has gone well, that folder is your only backup!).

Step 1: choose with the button marked with 1 in the photo

the folder which contains your pictures*

the destination folder will automatically become a folder called adjusted which is created by the program and placed into sourced folder, you can leave it as it is or you can change it if you want, this is your personal preference.

Step 2: in the time difference page (2) select the voice set time/date from (3) and then date in filename (4).

*when choosing the folder there are different scenarios: if your folder hierarchy is like DCIM with inside camera and screenshot folders, the app will look for pics in the DCIM camera but not in the folders inside so it will process no photos, you must choose a folder which has photos directly in it, the photos in subfolders will not be processed and you will have to repeat the process manually afterwards!

Step 3: click on options (5) and the only think marked should be "Set file date to taken date" this will ensure than the photo date will be embedded into metadata with the same date shown in the filename and will avoid strange conflicts with some gallery apps which read file date and not taken date. Also remember NOT to mark "use file created date to taken date". There is another option pre marked which

you should unmark which is "rename files to"**

**rename files to date option is useful if you have a few photos which have a name modified by you like "photo of mark" but have metadata and so show the correct date of when it was taken. I sugget to tailor use that option singularly on those kind of photos so the date is written in the file name and in case the metadata gets lost you have a backup, however when using the program to bulk change date of incorrect photos i would not advise to do that because it will add that to the name of all pics (which already have the date written in it) and it could be annoying. So use that function only on pre selected groups of photos with the overmentioned issue.

Step 4: check that in the advanced, privacy, filters and upgrade to pro everything is turned off.

Step 5: Hit process photos and wait for it to finish.

Step 6: After it finishes click on open folder or manually navigate indicated in destination folder in Step 1. You can rename that folder as you like (for example if you want it to be the camera folder of the phone rename it DCIM) and transfer it to your phone/sd card.

Step 7: check if all the photos are ok and there are no strange things going on with the date, if something is wrong delete the destination folder (indicated in step 1) and do all the process again. Again DO NOT DELETE THE UNTOUCHED PHOTO FOLDER ON YOUR PC TILL YOU VERIFY EVERYTHING IS OK BECAUSE IT IS YOUR ONLY BACKUP.

At this point all your photos date has been fixed!

Notes:

From my personal experience the photos with no date in filename are not modified by the program so if they have metadata it is not modified (if you marked what is indicated in step 3) and they will be fine, again cosider doing it for those photos only indicated in step 3 **.

If a photo keeps having the same behaviour after this process it is because it has not metadata and no date indicated in filename, so nothing can be automated. The date cannot be recovered via the file, but if you remember when you shot it you can permanently change with method 1.

I hope to have helped everyone!

Source: Solved: Photos lost date - Samsung Community