Content Writer Blog etc

We are Digital marketing startup needs Content Writer for the websites of our clients. We need content writer for Blogs, Advertisement, Page Contents, Product description. Candidate should be knowledge of Keyword research and keyword placement in blogs and page contents. Its a regular work therefore we prefer word based contact not hourly based. Right now I need 100 blogs of minimum 600 words. Candidate should place relevant images withing the blogs with the source of image or should send place the link of relevant image, so that we can place the right image. Candidate also suggest us the topics of Blog on the particular niche which we will provide them time to time.