When I had just joined here I was aghast at this kind of plagiarism and used to flag some of them. Then I realized that there are hundreds of them around and flagging them all takes up too much of my time.
It seems that they have run amok and some action needs to be taken from a higher level instead of relying upon individual members only to flag them.
There seem to be enough financial resources for Steemit to put together a team that checks posts before they go live, at least on a random basis so that the spammers who only copy and paste, and use others' images are stopped.
For the time being, Steemit does have good content, but it gets diluted by all the spam, posts of less than 100 words(usually plagiarized content) and single images(without content) belonging to someone else.
The worst thing is that these plagiarists achieve much more than sincere people here do, with some crossing 50 in rep in just a few weeks. They earn mere cents(people upvote their posts!) but posting ten times a day it all adds up for them and they are the ones who seem to be prospering the most on Steemit.
we all need to do our part. Steem is decentralized, so we need to be active and doing some work here if it is to succeed.