Firefox is a browser, it can not be used to access a camera, any camera.
If a camera has wifi or if it is connected by a USB cable it can be accessed by the file manager. You would just go to 'This PC' in the menu, there you would see the camera just as you see the C: drive and other devices you have connected to the computer. You would double click on the camera, navigate to the DCIM folder and there you would see your picture files. You can then copy the pictures to your computer; best to do that rather than opening them from the camera. You can use any program on your computer that opens jpg files; Firefox can be used if you want but you have to right click the file, select "open with" and then select Firefox. There should be a check box when you make the selection to set Firefox as the default to open jpg files. There are better programs to set as default. Windows 10 is set to the "Photo" app by default but it can be chanes to Firefox or any other app that handles jpg file.
All cameras and other connected devices work this way. You must use the 'My PC' to access the files before you can open them with any program or app including Firefox.
