The path is the one you choose with partimage in "Image file to create/use" on first screen. 2 cases: 1. If you entered absolute path (name starts by a '/'), it will be used as it. 2. You entered a relative path (name starts by anything else than '/'). The path will be related to the one you started partimaged from. If you only gave image filename, the path will be the current directory (where you started partimaged).
partimaged switched to 'partimag' user for security reasons but ion your system, this user can't write in the directory you choose to save images. You have to change permissions of the directory. Man chmod and chown can help you here.
First: run
Then, put partimaged.key and partimaged.cert into appropriate directory and chmod them 0600
If partimaged --chroot {your directory} doesn't fail, you'll be able to run partimaged as daemon into chrooted environment with `partimaged -D --chroot {your directory}'