Hello,,
Complete newbie here.  Sorry for posting in wrong place, if so.  I've been using Mavic Mini 1 and 2 for a while.  I've simply transferred photos to my phone.  Subsquenly transferred photos to my PC.  Lately, I'm unable to open any files on my PC unless I rename each file with an .jpg extension.  I take hundreds of photos for work, so this is not a good solution.  Being a newbie, I'm not sure were to find solution.  Thank you for help.

Take the SD card out of the drone and use a card reader to access the original images.  

There is software for renaming and changing the file extension for many files at once. I use eg Advanced Renamer or similar. You don't have to do this by hand for every photo.