Is it permissible to attend a doctoral graduation ceremony in a Western country, wear the special attire (cap and gown), and be photographed in them for memorabilia, knowing that attendance is not necessary and the degree can be obtained without it?

It is forbidden to wear a graduation gown if it is specific to or a symbol of disbelievers, due to the saying of the Prophet (peace be upon him): "Whoever imitates a people is one of them." If it is not so, then there is no harm in it, though it is preferable to avoid it. If the ceremony involves unlawful acts, then it is not permissible to attend it, due to Allah Almighty's saying: "And He has already revealed to you in the Book that when you hear the verses of Allah being denied and ridiculed, then do not sit with them until they enter into another conversation. Indeed, in that case, you would be like them. Indeed, Allah will gather the hypocrites and disbelievers in Hell all together." (An-Nisa: 140). Filming the ceremony with video is permissible, but still photography is a matter of dispute, and it is advised to avoid it to steer clear of controversy. It is also advised not to attend this ceremony as long as it is not necessary.