open folder with gthumb?

Hello. How can I open a folder with gthumb in an easy way? I right click in gnome, select "open with other applications", and select 'gthum', this really works, but, nautilus won't remember this, next time I right click a folder, 'gthumb' is still not there. How can I make "open with gthumb" appear in the right-click menu? For me selecting gthumb from 100 application list is easy, but it's a bit too difficult for really dummy users who I need to support. -- 锐业软服（国内业务） http://www.realss.cn Real SoftService http://www.realss.com 销售咨询(Sales Department): 0086 592 20 99987 (Chinese, German, English) 国际业务(International Sales): 0086 10 8460 6011 (German and English) 联系：厦门大学科技园，嘉庚二号楼6楼 邮政：厦门大学2312号信箱（邮编361005）