I recently worked with a company to convert a large number of high resolution photos in the .tiff format to the more usable 4096x2160 in the .png format. I looked into a lot of solutions and finally settled on Image Magick for it’s low overhead and high customability. I used the Image Magick CLI tool which was easy to install on the remote Windows platform I was working on.
I wrote two .bat files. One converts the photos at original quality and the other converts the photos to a lower resolution.
Original Resolution
magick mogrify -format png -path "./Original_Resolution" *.tiff
Lower Resolution
magick mogrify -format png -path "./Lower_Resolution" -resize 1920x1080 *.tiff
Check out the repo: .tiff-2.png-scripts
Photo Credit: https://imagemagick.org/index.php