I'm gradually getting to grips with my light tent, but now find I need to edit differently. I've been using Irfanview for years and had therefore ignored various people's advice to try Picasa until recently.
Thank you LushandLovely!
Picasa is very user-friendly, and joy of joys it lets you crop to a square! That's one of the many things that has been such a trial for Folksy and Etsy - I 've cropped to what I feel sure is a square, only to then have somebody's head chopped off in the thumbnails.