The advantage of having a copper membership is not just for images it also reduces the time limit for posting or PMs and you can also do what member ranks do.
The only thing that you can't able to do with copper member is that wearing an Avatar if you are planning to wear avatar you must reach the full member rank.
Read the "
Enhanced newbie restrictions & requirements" so that you know what is newbie and Jr. members rank limit and most of the listed restriction can be lifted after buying a copper membership.