Hi there thanks for your post! We sometimes find that photos inserted from publically accessible web locations (such as Linkedin) can stop working in your org chart if the image URL changes (see this Community post for more information about the issue.) Please also note that you cannot use links to images stored on Google Drive as Google Drive will block Lucidchart's access to the images.

However the behaviour you described is quite unusual as the issues described above would typically affect the visibility of photo in the Lucidchart editor (not just when printed). As a first step could you try uploading one of the missing photos directly to Lucidchart (assuming that they are currently linked from a web location)? Once inserted please try printing the diagram again to see if the issue still exists. For more information on manually uploading employee photos please see this section of our Org Charts article. 

If this doesn't help would you mind submitting a support ticket using this form so we can investigate the issue further? Please make sure to include the URL of the affected diagram and a screenshot of the issue. Thanks!