To legally obtain Cisco IOS images, you generally need a Cisco account with an active service contract. Spiceworks Community Cisco Modeling Labs (CML)

: This is the current and preferred method for getting modern Cisco images (like IOSv, IOSvL2, and ASAv) for GNS3. You can purchase a subscription at the Cisco Learning Network Store Physical Hardware Extraction

Once you have the image file, follow these steps to add it to your environment: Open GNS3 and go to Edit > Preferences For Dynamips (Legacy) : Navigate to IOS Routers > New and browse for your image file. For CML/VIRL Images : Navigate to Qemu VMs > New or use the GNS3 Marketplace templates for a guided import.