In Photo Gallery 2012, I do not know how to search for part of a filename.

I have some files that are older and were named before spaces were allowed in the filenames.  

When I use "Text Search" from the Find menu, it only finds the file name if the text search is the first word or is found after a space.   Example:  a search for files with the name Janet does not return these files:   RickJanetPam  or Pat_Janet.            (Files named     Pat Janet      do show up.) 

I have tried %Janet%  &Janet& and *Janet* with no success.