This video tells you how to Transfer files over wifi from Windows phone 8 devices .
Download the following app to your windows phone
Kuchiyose ( Windows Store ) : http://goo.gl/T4Vhos
Then follow the instructions on the video
Alternative apps :
Easy Transfer : http://goo.gl/9tNgNe
Wifi File Sharer : http://goo.gl/m0re4i
Comment below for any questions !!!