[unix] How to use find command to find all files with extensions from list?

I need to find all image files from directory (gif, png, jpg, jpeg).

find /path/to/ -name "*.jpg" > log

How to modify this string to find not only .jpg files?

in case files have no extension we can look for file mime type

find . -type f -exec file -i {} + | awk -F': +' '{ if ($2 ~ /audio|video|matroska|mpeg/) print $1 }'

where (audio|video|matroska|mpeg) are mime types regex

&if you want to delete them:

find . -type f -exec file -i {} + | awk -F': +' '{ if ($2 ~ /audio|video|matroska|mpeg/) print $1 }' | while read f ; do
  rm "$f"
done

or delete everything else but those extensions:

find . -type f -exec file -i {} + | awk -F': +' '{ if ($2 !~ /audio|video|matroska|mpeg/) print $1 }' | while read f ; do
  rm "$f"
done

notice the !~ instead of ~

On Mac OS use

find -E packages  -regex ".*\.(jpg|gif|png|jpeg)"

In supplement to @Dennis Williamson 's response above, if you want the same regex to be case-insensitive to the file extensions, use -iregex :

find /path/to -iregex ".*\.\(jpg\|gif\|png\|jpeg\)" > log

find /path/to/ -type f -print0 | xargs -0 file | grep -i image

This uses the file command to try to recognize the type of file, regardless of filename (or extension).

If /path/to or a filename contains the string image, then the above may return bogus hits. In that case, I'd suggest

cd /path/to
find . -type f -print0 | xargs -0 file --mime-type | grep -i image/

find /path/to/  \( -iname '*.gif' -o -iname '*.jpg' \) -print0

will work. There might be a more elegant way.

find -regex ".*\.\(jpg\|gif\|png\|jpeg\)"

find -E /path/to -regex ".*\.(jpg|gif|png|jpeg)" > log

The -E saves you from having to escape the parens and pipes in your regex.

find /path -type f \( -iname "*.jpg" -o -name "*.jpeg" -o -iname "*gif" \)