Welcome to the wiki Zuqi. I saw some of your messages recently, and I see you're off to a flying start with some bold editing. -- Haha, don't take that the wrong way ^^" I mean it in a good way, that you're willing to put your thoughts out in the open and explain them, but willing to listen and discuss in case you find another reason more appealing.
One thing I wanted to comment on: I'd seen you said at least twice that you especially wanted admin answers for a few questions in particular. I understand why you asked that, and truly I do appreciate it, but I want you to be aware that policy is available for all users to see - with its main page located at Project:Policy. All of our rollbacks should have an understanding of policy as well, so any of them can be just as approachable. Even so, we have other users who are not rollback that likely could give some guidance too.
What I mean by all that is; the wiki is open to everyone. Even users with no user right status can cite policy and offer help here, as this community should thrive together as one and help each other. Administrators are only here to try to help keep the site running at its best, or as a term I've said a long time ago, we're the "janitors of the wiki." hehe =]
Nice to have you join us! Hope you like it here. If you ever have questions, you can bring it up on the message wall of anyone you see active at the moment, or mine, or another admin, rollback, etc. Ah; you'll figure it out well enough. ^^"
I have a question about the suggesting profile image changes. I submitted a proposal today to change the image for Pabu, but it was rejected. What is the proper way to address the reasons for rejecting the proposal? There were 2 reasons given for rejection, one of which I have no problem with (using the same image for multiple profiles) and one that I disagree with (Pabu doesn't normally wear clothes, so his profile shouldn't show him wearing clothes). Also the rejection doesn't take into consideration that the current image is also not an accurate representation of Pabu.
Where exactly should I voice my concerns? By adding text in the "rejected proposals" section. Or should I just look for a better picture and submit a new proposal?
The best way would be to look for a better image that doesn't depict Pabu wearing those clothes. You are right that the current image doesn't portray him as usual either. I actually don't know where you could voice a "complaint" about the reasoning. I would say that you either said that on the talk page of the profile image change or on the message wall of the admin that rejected the proposal (in this case, Thailog). Anyway, don't be discouraged about a rejected proposal, that happens all the time. I'm glad that you are taking the time to look for a decent image to put on our articles :-)