I need a good photo of people reaping hay by hand ...

Good luck finding that.  Most people who grow hay do so to make money and so it has to be grown in bulk.  Hence, the use of machines.  I Googled the subject, found several articles, but few pictures.  Scything is an old art, so I'm not sure where you will find it unless it is an old painting, or perhaps a reenactment at a place like Historical Williamsburg, or perhaps Sturbridge Village in MA.

Good luck!

You might be able to find such a picture in Amish country.  Lancster, PA is well known for their Amish community, but there are also many Amish in other states such as east central Ohio and northern Indiana.  The only problem with this is that many of the Amish do not want you to take their picture.  However, there are usually post cards and other photos available for sale in the Amish areas.   

You might also try your public library for books about the Amish and see if they contain any pictures of people reaping by hand which you could scan.  You could also try putting in the word Amish on the Internet and try some of the sites that come up. 

I found a site that contains beautiful photographs by a professional photographer, Bill Coleman.  It is at the following web address:

http://www.amishphoto.com/galleryindex2.htm

If you scroll down and click on the picture that says "Fall Scenes" you will find some nice pictures of Amish people working in the fields and putting hay on a wagon.  However, I don't know if you can use these pictures because they are for sale by the photographer and quite expensive.  But they are very nice. 

I hope this helps.