Openning a remote file, https problems

My site opens a remote file for image manipulation. If I go to my site using http, then all works well and everyone is happy. However, if I visit my site using https, then I get an error that it is unable to open the remote file. I searched throughout the PHP site for awhile and was unable to find any documentation on this matter. What could be the possible problem? Thanks, Daniel Hemmerich <dan><spot.org> Home Site: http://www.spot.org/ BSD Site: http://www.BSDpro.com/