Arista offers the vEOS lab images for free on their website to registered users. Juniper provides evaluation copies of vMX and vSRX. Step-by-Step: How to Install Downloaded Images in EVE-NG

Because EVE-NG is just the "engine," you must provide the "fuel" (the images). The only strictly legal way to obtain these for simulation is through official vendor channels. Cisco Images (IOS, IOS-XE, NX-OS)

It is crucial to address the ethical and legal implications surrounding image downloads. The democratization of network education relies heavily on the accessibility of these tools, yet software licensing remains a strict legal boundary. Using vendor images without a license is technically a violation of copyright and end-user license agreements (EULAs). For professionals, this presents a dilemma: the need for hands-on practice versus the obligation to adhere to software compliance. The consensus within the professional community is that while using images for personal lab study is widespread, it should never be used in a production commercial environment without proper licensing. Furthermore, users must be vigilant about the sources of their downloads; obtaining images from untrusted "warez" sites can expose the host system to malware and corrupted files.

Open your terminal and into your EVE-NG instance (you can use built-in SSH tools or a client like PuTTY).