why do some of my picturess have their heads cut off when printed out but are ok on the pc screen?

Answer 1

This is due to the different aspect ratio of the original digital photo (4x3) and the printed photo (4x6, 5x7, 8x10, etc) - here's a FAQ from Shutterfly - an online print service - that explains this:
http://crmweb.shutterfly.com/cgi-bin/helpfly.cfg/php/enduser/std_adp.php?p_faqid=140&p_created=1127321007&p_sid=Zy18pTxi&p_accessibility=0&p_lva=&p_sp=cF9zcmNoPSZwX3NvcnRfYnk9JnBfZ3JpZHNvcnQ9JnBfcm93X2NudD05OCZwX3Byb2RzPSZwX2NhdHM9JnBfcHY9JnBfY3Y9JnBfc2VhcmNoX3R5cGU9YW5zd2Vycy5zZWFyY2hfbmwmcF9wYWdlPTEmcF9zZWFyY2hfdGV4dD1jcm9wIGZhY3Rvcg**&p_li=&p_topview=1

Answer 2

Your camera sensor is not shaped like a 4x6, it is more square, ie, a different ratio. So when you print a picture size that is more rectangular, part of the image is lost on the edges. When printing 4x6s or 5x7s, you will need to crop the image so the heads are left on. That may mean you will have to eliminate the feet! If you're printing at a kiosk in a store, you usually can see the result of the crop before you print.
Try to leave a little space around the edges for crop room, but don't get too far away!