Okay, I need to classify this bug report as either 'user-mode' or 'system-mode'. Let me first understand the problem. The user is reporting an issue with `qemu-img` where it doesn't accept a full file path for the backing image. They tried using `-b test/a.img`, but it didn't work, forcing both images to be in the same directory. When they used just `a.img`, it worked. So, `qemu-img` is part of QEMU, which has user-mode and system-mode components. User-mode deals with emulating hardware for virtual machines without needing kernel-level privileges. It includes tools like `qemu-system-*` and utilities like `qemu-img`. In this case, the problem is with `qemu-img`, a command-line tool used for managing disk images. Since it's handling file paths and creating snapshots, which are user-space operations, it falls under user-mode. The issue doesn't involve device drivers or kernel interactions; it's about how the tool processes its arguments. So, this bug is related to user-mode. user