Family Tree Maker has a Media Folder for each Family File.
You have a number of options. I can only tell you what I do.
I actually have two copies of anything that I put into Family Tree Maker. The first copy would be on an External Drive where I have all of my Photos, where I file them by Family Tree Maker File.
The trick here, is Filename, for me at least. I name the files so I know what they are. Usually, Surname_First_Middle_Date_Event for the format, or some variation on that.
Now, I want to add that photo to Family Tree Maker. I Add that Media File for the Person, navigate to the External Drive and COPY that file, from the External Drive to the Media Folder for Family Tree Maker.
The next piece is the Caption for that Media file within the Media Workspace in Family Tree Maker.
Family Tree Maker allows you to Sort the Media Workspace by Filename or Caption. The caption is easy to see on the screen, the filename is there, but you have to select it to see the filename.
If you use the File, Back Up and Include the Media, it will back up your data and the media files into one file. You would then do a File, Restore from Back Up and your data and media files will be restored.
Hope that helps,