AppleScript to convert + compress HEIC images to JPG. Can be compiled into an Application with Apple Script.

.convert-heic-to-jpg.sh

#!/bin/bash
# Converts all .HEIC files in directory ($1) to .jpg
# Outputs converted images to $2

if ! command -v /usr/local/bin/magick &> /dev/null
then
    echo "magick could not be found, you need to install it."
    exit
fi

for f in $1*.HEIC
do

DIR_NAME=`dirname "$f"`
BASE_NAME=`basename "$f"`

	/usr/local/bin/magick convert "$f" \
			      -sampling-factor 4:2:0 \
			      -strip \
			      -quality 65% \
			      -interlace JPEG \
                              -gaussian-blur 0.05 \
			      "$DIR_NAME/$2/$BASE_NAME.jpg"
done

echo "Done."

.current_datetime.scpt

(*
	The zero_pad function taken from:
	http://www.nineboxes.net/2009/10/an-applescript-function-to-zero-pad-integers/
*)
on zero_pad(value, string_length)
	set string_zeroes to ""
	set digits_to_pad to string_length - (length of (value as string))
	if digits_to_pad > 0 then
		repeat digits_to_pad times
			set string_zeroes to string_zeroes & "0" as string
		end repeat
	end if
	set padded_value to string_zeroes & value as string
	return padded_value
end zero_pad

on run
	set now to (current date)
	
	set result to (year of now as integer) as string
	set result to result & "-	"
	set result to result & zero_pad(month of now as integer, 2)
	set result to result & "-"
	set result to result & zero_pad(day of now as integer, 2)
	set result to result & "@"
	set result to result & zero_pad(hours of now as integer, 2)
	set result to result & "-"
	set result to result & zero_pad(minutes of now as integer, 2)
	set result to result & "-"
	set result to result & zero_pad(seconds of now as integer, 2)
	
	return result
end run

heic_to_jpg.scpt

set script_name to ".convert_heic_to.sh"

tell application "Finder"
	set current_path to container of (path to me) as alias
end tell

set postix_path to POSIX path of current_path
set current_datetime to run script postix_path & ".current_datetime.scpt"

tell application "Finder"
	set current_path to container of (path to me) as alias
	make new folder at current_path with properties {name:current_datetime}
end tell

set scriptcommand to postix_path & script_name & " " & postix_path & " " & current_datetime


do shell script scriptcommand

display dialog "Done"