It's a lot better to do this in bash, zsh's expansion/glob facilities are too smart for their own good and mess up some of the commands.
wget --random-wait -e robots=off -U mozilla https://manuals.co/workshop/dodge/ram/dodge-ram-1990-workshop-manual-rear-wheel-drive-truck/5575968/{1..1134}
grep -o s3.eu.west.1.amazonaws.com.manuals.co.5575968.bg.\*.png * | sed -e "s/:/.png https:\/\//g" | sed -e "s/^/wget -e robots=off -U mozilla \-O /g" > wget.sh
bash wget.sh
ls | grep -v .png | xargs rm
rename 's/.png$//' *
for f in *; do mv $f `printf %04d ${f}`; done
rename 's/$/.png/' *