Hi shadowsjc, yep my gallery is the latest version 5.3.17.311.
Previously I had already explored the other idea you mention with the drop down menu from Instagram and yes after digging around I can get to the pics and vids that appear in 'My Files' however they are either grayed out which means I can't select it, or in the case of a vid when I tried it, it flicks to Instagram momentarily then flicks back to 'My Files' and doesn't allow me to send it via Instagram or I thought it may save in drafts but it doesn't.
Believe me I have spent many hours trying to resolve this and there really is no way. I was hoping by the off chance that perhaps there was something I was missing but I am starting to believe it is a gross error on Android phones. After reading forum after forum its not an exclusive problem just on the S8+ but all Android phones.
I understand that the phone is doing the right thing by saving it to 'My Files' as the Gallery is simply an app, however, it doesn't explain why sometimes pics will save to the gallery and other times in 'My Files'. There is no logical reason for that to be happening. I even did a test. I repeatedly sent myself the same picture via the same email system multiple times (7 times in fact) and I could save the same pic to my gallery each time. I was attempting to get the same pic to eventually save to 'My Files' only and you guessed it, after seven attempts suddenly on the 8th attempt that very same picture that saved 7 times to my gallery then decided to save only to 'My Files.'... it really makes no sense for the phone to pick and choose when it wants to save to gallery and when it wants to save to 'My Files'... unless the phone is becoming self aware and wants to do its own thing
It really is a problem that needs to be addressed by Samsung considering that 99% of Samsung users would also be Instagram users I suspect and considering there are forums after forums of people with the same issue I'm surprised it hasn't already been resolved by Samsung.