This command line script will download the entire Magento 2 media folder in seconds, and exclude the dreaded cache and tmp folders. You can use it to download a media folder to your local filesystem or sync media folders between servers.

rsync_media.sh

#!/usr/bin/env bash
# Download all media from the production server, except for cached files.

# SET VARIABLES HERE

# 1. SSH connection
SSH_PRIVATE_KEY="~/.ssh/YOURPRIVATEKEY"
SSH_PORT=22
SSH_USER="YOURUSER"
SSH_HOST="YOURSERVER.COM"

# 2. Paths. Include a trailing slash!
REMOTE_PATH="/remote/path/to/magento2/pub/media/"
LOCAL_PATH="/local/path/to/magento2/pub/media/"

# 3. Paths and files to exclude, separated by a space. You can also include files
EXCLUDED_FILES="catalog/product/cache images/cache sitemap tmp"
EXCLUDED_FILES_FILENAME="excluded-media-files.txt"

# DO NOT EDIT BELOW THIS POINT
printf '%s\n' $EXCLUDED_FILES > $EXCLUDED_FILES_FILENAME
rsync -arve "ssh -p $SSH_PORT -i $SSH_PRIVATE_KEY" $SSH_USER@$SSH_HOST:$REMOTE_PATH $LOCAL_PATH --exclude-from $EXCLUDED_FILES_FILENAME