Every file on your device has a "date file created" and "date file modified".
In addition, pictures and videos have "date image created" and "date image edited" in their EXIF data inside the picture/video
The file dates have nothing to do with the image EXIF dates except that when the image was first created on its original device, the file creation date matched the image creation date.
Some apps will update the file dates when a file is copied, some will not. This is kind of a philosophical debate.
Many poorly written image viewer apps will wrongly look at the file dates when they should be looking at the EXIF dates because the programmer was lazy and looking at the file dates is easier.
Many (most or all?) mobile devices use the image creation date to name the file that is saved. This is nice since you can do a sort by name and get the same results as a sort by "image creation date".
If you need a picture viewing app that gets the dates done correctly, take a look at "piktures" by Diune.
https://forums.androidcentral.com/e.../details?id=com.diune.pictures&token=evk1YsmT