Restoring files from mounted image

Hi. I'm trialling your diskmaster software and have a question. After capturing an image from your WinPE environment to a USB hard drive, I try to then mount the image in Windows and browse files. The image mounts successfully but some files are not accessible due to permissions. When trying to adjust security permissions, I'm unable to do so because the image file is mounted as read-only. How can I mount images as writable so I can add permissions as needed?