It seems like some people like to put the lastest vol pic in the manga information page BUT that sometimes gives HUGE spoilers in the series and we really should stop doing it, dont know make some kind of gallery where people can upload vol pics but not the information page... we should have there only vol 1... its weird people lets stop. Even when it doesnt really spoil as the series is so FOWARD in time the pic doesnt really portrait the plot in the start and may lead to confusion.

Using covers for the series image that spoil anything is not allowed; please report it if you see any images like that posted.

Personally, I agree about using the first volume's cover as the image, but there are a few who like the latest volumes and who have worked very hard to post those for a lot of series. Although it doesn't make me particularly happy either when later volumes are used, just try to keep in mind that the most important thing is that a cover image is there at all. (Also, which volume people want to see is a matter of personal preference.) Having a later volume featured, while in my opinion not ideal, isn't bad enough to have a rule made against it.

About the cover gallery, it was definitely suggested before, but I don't think it's likely to happen because of the coding & organization as well as data storage space that would be required.

Manga Cover Database

Okay ! i will take the spoil part in mind if i see anyone!, thanks for answering!