I always try to rewrite article with my own words. When I write a post, I read about it on different sources, I take the infos I believe be more important and then rephrase in my own words.
Is it plagiarism? I don't think so
About images, I will pay attention to put the source although they are taken randomly from internet (on some posts, not on posts where I say that the pictures are mine).
A partial rewrite is something funny, because, for example, writing "Germany defeated Chile in the Confederation cup final with the result of 1-0" may easily incur in "partial rewrite" although I have wrote it right now from scratch.
I completely agree with fighting plagiarism and people simply copying and pasting content from other website. I hope these bots will be improved, otherwise it will be impossible to write any news on Steemit without being finger pointed for plagiarism.