Change logo path to https

Hi. I have completed my site and integrated an ecommerce program. Everything is working except that the is a security warning when the consumer is returned from ecommerce page to the other site pages. I have done some research and it has been suggested that the warning is being generated because the path to the logo is http and not https. I can not seem to figure out how to change the path. I would appreciate any suggestions. Thanks! MaryJo