Just rename the .dd extension to whatever format the picture was in (i.e. .jpg/.png etc.) o.o
Before posting your opinion, no matter how noble and sincere your intentions to help others, I'd suggest that you rather first learn about the topic because you clearly have no idea about this.
The *.DD extension (for archive images, not picture images) is not a single file, but rather an archive in the form of a file. Meaning it's like a .zip file, or .bin or .rar. Meaning it contains a lot of other files.
Anyway, to anybody still reading this, the program you used to restore the data through an image does supply a method of opening the archive and extracting it, and the instructions are there. Just gotta look carefully. :P