Don't Panic - Photo Edition is a photo recovery utility. The windows version of this application is called Image Recall, and it offers the same functionality. The app uses a wizard to guide you through the process. When you first launch it, there will be five options available. You can recover images, which will start a new scan, you can view your recovered images in previous scans, and you can open the advanced toolbox, with tools that are more specific than a simple scan for recoverable photos. The last two options let you access the help guide and purchase the full-version of the software, if you are running the trial.
Don't Panic - Photo Edition was designed to scan USB flash drives and memory cards. It won't be able to scan your hard drives. When you start a scan, the progress will be shown on screen. The number of found files, the current file being scanned, and the status, along with a progress bar will all be displayed during this step. In my testing of this app, during the scanning process, the window become unresponsive and the Mac spinning wheel was visible during most of the time. The data on the screen was updated from time to time, but not smoothly. I was OK with this, but then the application crashed a couple of times during scans.
To sum up, I haven't been able to recover a single photo using this application. Unfortunately, it crashed during its scan of my flash drive and I didn't get a single result when I looked for recovered files.
There is a trial version for this application, so you can try it and see if it works for you.