A. As you have accidentally found out, cameras require photos to be in specific places with specific naming conventions. The directories on the SD card will have specific names. Usually the image files themselves are sequentially numbered, such as IMG_01281.jpg
The exact naming will depend on your specific model of camera.
The first step is to back up the photos to the computer so you don’t lose them.
A question for you: why do you need the photos to show up in the camera? Is it okay to just have them on the computer?
Next, using a different SD card, take some photos. Then look at that card on the computer to see what the directory name is and how the image file names are structured.
Then rename the files on the first card to match that format, counting backwards from the number of the first new photo you took. If you have more than 100 photos, you may have to create additional folders
Often, the first level directory on the card is named DCIM (digital camera image), additional folders are created within that for ‘camera rolls’ which may have a limit of 99 or 999 photos per folder, depending on the brand. Each brand of camera has their own operating system and conventions for naming. here is one example
Finally, don’t rename, reformat, or move things around on a SD card with a computer. Do your formatting in the camera and otherwise leave the card alone.
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