feh bash function/alias , It will search current dir and subfolders for .jpg,.jpeg & .png files and write them to a file in /tmp/ (e.g /tmp/filelist-4Gf) the last 3 characters are random. feh will then load the filelist and sort the files by modified time, display filename, auto-zoom and 800x600 resolution.

feh bashrc bash function

fehl() {
    randomfile=filelist-$(< /dev/urandom tr -dc A-Za-z0-9 |head -c 3).txt
    find . -type f \( -iname "*.jpg*" -or -iname "*.jpeg*" -or -iname "*.png*" \) -printf "%p\n" | grep -v /thumbs/ >>  /tmp/$randomfile ; feh -d -S mtime  -Z -g 800x600 -f /tmp/$randomfile &
}