The simplest, and quickest, way to move them all back would be to connect the phone to a computer, via USB cord. Move all the items off the SD card into an empty folder on the computer. Then, while still connected via USB cord, copy all that over to the phone.
To do it only the phone only will usually not allow for moving all the files at once, meaning it would take a lot more effort.
NOTE: To get your photos to save to the phone, in the future, and not to a card, you would need to change the settings in the camera app. Also, I would really suggest backing up all personal stuff off a phone onto a computer or cloud account regularly. Phones die, get lost, get stolen, things get deleted, etc.