You can still create system recovery images using wbadmin, the backup command line tool.
From a Powershell prompt, the command to create a recovery image is:
wbadmin start backup -backuptarget:z: -allcritical
where z: is the destination drive letter.
To save the image to a network share, the command is:
wbAdmin start backup -backupTarget:\\share\sharename -user:user -password:pass -allcritical
Once the backup process is complete, you will see the familiar "WindowsImageBackup" folder structure in the backup destination location.
To restore the image, boot the system from the Windows 8.1 installation media (this is important). You can't do this from the F8 recovery options. Once you've booted from the media (CD/USB), select Repair Your Computer...Troubleshoot...Advanced Options...System Image Recovery. From this point it's the same restore process as with Windows 7/8.