Fix imgur mistakes :( These one liners rename files with jpg extension to gif extension if their mime type is image/gif, after replacing spaces with underscores and jpeg with jpg.

fixgifs.sh

#!/bin/bash
# depends on `brew install rename`

cd ~/Pictures/pics
find . | rename 's/\ /_/g'  
find . -iname '*.jpeg' | rename 's/jpeg$/jpg/g'
find . -iname '*.jpg' -exec file -F '' --mime {} \; \
| grep -i 'image/gif' | awk '{print $1}' \
| while read file; do bn=`basename -s .jpg $file`; mv $bn.jpg $bn.gif; done