One possible way to show most recent blog posts is to use the Feed Manager Feature to consume the RSS feed of the blog, people often do this to show the most recent blog posts on their home page.

There are some ways to make it possible to show certain content instances such as a Feed Manager on multiple or all pages, but I think what I would do for something like that is find some javasacript or jquery rss feed reader that could be embedded in layout.master file and configured with the feed url for the blog. Usually something like that will be lighter weight and more configurable.

For an image per post one could put the image in the excerpt of the blog along with a brief summary of the post and configure the blog to use the excerpt in its rss feed.