ImageMagick

https://imagemagick.org/script/download.php


@echo off
setlocal enabledelayedexpansion

REM === Set your Google Drive folder path here ===
set "target=C:\Users\%USERNAME%\Google Drive\Photos"

cd /d "%target%"

for %%f in (*.heic) do (
echo Converting %%f ...
magick "%%f" "%%~dpnf.jpg"
if exist "%%~dpnf.jpg" (
del "%%f"
)
)

echo All HEIC files converted and originals deleted.
pause