wow this is still an issue from 2013!!??
is prestashopmanager the way to do it - can it be done using the trial. My img dir is 2gb!
im confused as to what regen thumbnails actually does? does it not tidy up the img directory?
NOTE:i found this - gonna give it a try https://boutique.comonsoft.com/gb/free-prestashop-modules/27-regeneration-of-prestashop-images.html