I have seen that many people use images from google, other websites, etc in order to make majlis invites, etc. These images available online have copyrights on them. However, is it permissible to use them, without taking permission from the owner, if we are using them to make majlis invites, i.e, personal use of them

Regarding your question specifically, and as the internet is usually common usage for people, there is no problem in using the image for general material, but perhaps seeking permission is better out of precaution, and Allah knows best