No, those photos are stored in a temporary file that turns itself into images by the program. If the program crashed, then the files are deleted as well.
Even if you try to recover the contents of the file you wouldn't know how and where to cut each files and for the 300 pictures, it could take very very long.
Rescan the images, but this time save each image after it was scanned, not all of them in one go. It saves time, it allows you to split the time and get back from where you left if something else happens with Easy Photo Scan.