This is Kali Linux's base-images repository:
https://cdimage.kali.org/

Your nearest mirror:
http://cdimage.kali.org/README?mirrorlist

Grab the latest images from the "current" directory:
https://cdimage.kali.org/current/

Download Kali Linux ONLY from official mirrors!
https://www.kali.org/docs/introduction/download-official-kali-linux-images/

If you need older images, you can find them on:
http://old.kali.org/kali-images/

More information about Kali Linux's mirrors:
https://www.kali.org/docs/community/kali-linux-mirrors/

Kali Linux, The Most Advanced Penetration Testing Distribution. Ever.
https://www.kali.org/