I have a S4 mini and some of my photos do not work, how can I get my pictures images back to normal?

[AC Question]

I have a S4 mini and some of my photos do not work!

I changed some of my screenshots and photos to my SD card and then once I changed it back to my phone then to the SD card again. Now some of my images do show the pictures they just appear blank with a black background and a grey little square in the middle showing that the image is damaged or something. Idk how to get the images baCK! PLEASE HELP