Can't import

I'm running 10.10.3 and cannot import photos anymore. Originally I thought it was a problem with Photos, so I switched back to iPhoto (9.6.1), but the problem remains. The import message reads "The file is in an unrecognized format", although it's recognized all of my previous imports of JPG files from my camera. If it helps, one of the photo/file names is "IMG_7708.JPG". Any help would be much appreciated.

Thanks.