#!/bin/bash
s="123.jpeg
123.jpg
123.bmp
123.png
234.JPEG
234.JpG
234.bMp
234.pNG
677.txt"
echo "$s" | awk '
BEGIN {count_photo=0;} {
if (tolower($0) ~ /\.(jpe?g|png|bmp)$/) {
count_photo++
}
}
END {printf "%s\n",count_photo}'
IyEvYmluL2Jhc2gKcz0iMTIzLmpwZWcKMTIzLmpwZwoxMjMuYm1wCjEyMy5wbmcKMjM0LkpQRUcKMjM0LkpwRwoyMzQuYk1wCjIzNC5wTkcKNjc3LnR4dCIKZWNobyAiJHMiIHwgYXdrICcKICAgIEJFR0lOIHtjb3VudF9waG90bz0wO30gewogICAgICAgIGlmICh0b2xvd2VyKCQwKSB+IC9cLihqcGU/Z3xwbmd8Ym1wKSQvKSB7CiAgICAgICAgICAgIGNvdW50X3Bob3RvKysKICAgICAgICB9CiAgICB9CiAgICBFTkQge3ByaW50ZiAiJXNcbiIsY291bnRfcGhvdG99Jw==