Why can I see the thumbnails of photos contained in a folder but cannot open and view them?

[CompNovice]

I am not very skilled with computers in general but even more clueless with the recent change from Windows XP to Windows 10. When I got my laptop back from tech he had saved all my pictures and documents-most photos appear in the "my photos" section. Since then, I have imported photos from my iphone a few times and didn't look to see where it said they were being saved. After much unnecessary (for most) searching, I found them in folders located after searching "my documents". Below "pictures" it has 3 empty yellow folders with dates beside them. When I click on any of those folders the file with all the photos with thumbnails comes up. Instead of the usual "jpeg" with a number under the thumbnail, these have "IMG_" and a number below and when I right click and choose "open"- it immediately opens a screen titled "photos" and then NOTHING. Within 30 seconds the entire box disappears and it returns to the file contents with all the thumbnails. Even as a novice-that tells me the photos are there. Why can't I open any of them and how can I fix it. Please make the instructions clear and simple...I'm having enough trouble as it is. Thanks

 

[Trouble]

Right click one of the problem image files in file explorer and from the context menu choose Open with -> Paint
Does it open as expected or does it offer an error message of any type?