Hi Kimberly,
Please try the following steps:
Starting with Mojave (and double-downed in Catalina) you need to
1) go into your computers "System Preferences" and select the "Security & Privacy" option and select the "Privacy" option.
2) On the left hand side scroll down until you see the option of "Full Disk Access" and click on that.
3) On the bottom left of the window you'll see a lock, click that and put in your administrator password.
4) Now, click on the "+" symbol that lets you add applications to the list on the right hand side of that window.
5) Find the Bridge application, select it, and click OK. Be sure that the check box next to it is checked.
When you close this window, the lock will automatically lock again so there's nothing to do there.
OK, One of the biggest problems that Catalina has given us is the need to have to change permissions on folders. Have you checked to see if the folder the original files are in have their permissions set to allow Bridge (or any application) access?
In the Finder select the folder that you're documents/images are contained in and press Command-i (i for information). A new window will pop up on the left side of the screen. On the bottom you will see a region called "Sharing & Permissions:"

To do anything here, you need to unlock the padlock on the bottom right. Click it and a window will pop up asking you for your authorization (your Mac password). Once that's done, click on the "Everyone" and on the right change "Read only," to "Read & Write."
Now, if there are folders inside this, go to the dropdown gear below and select "Apply to enclosed items..." and you can save yourself some time.
HOWEVER: be judicious when you do this. This should ONLY be done if there are nothing but documents inside these folders. Never EVER do this if there are applications or preferences or other application-related files. Don't ask me how I know this to be true. Otherwise, I do this all the time as necessary.
Please let us know if any of this works, thanks!