There has been somewhat of a confusion over what Blog images are and how it is used. To sum it all up, think of Blog Image a way for you to identify your blog post with an image.
Why should I use the blog image?
It helps you organize things! Consider this scenario, you have 100 active bloggers on your site, and each of them has different writing convention. This results in a complete mess of your blog's layout.
Unless of course, you clearly indicate that images should always be aligned to a specific alignment but come on, it's going to be crazy informing this to all your active bloggers.
In this case, blog image solves issues like this and you never have to worry again how is the image being added into the post. The blogger only need to select an image for the blog post. That's it! Everything else would be controlled by the theme :)
Where else would blog image used on?
Basically everywhere. If you are considering setting up autoposting to Facebook, Twitter, LinkedIn or even allowing your user's to share posts on Pinterest, defining a blog image would also mean that EasyBlog will pick the correct image to send to these social networking sites. No more confusions over which image is getting picked!
What other benefits of using Blog Images?
When using blog images, as a template club or as a web master of your site, you can customize the theme and have it displayed in different sizes / aspect ratio based on your liking as EasyBlog will resize the file (Physically) and you can then have it appear in your respective layout.
Consider that you are trying to just display an image with the size of 128 (w) x 128 (h). In a conventional way, this can be fixed by using css where it is hard-coded to have a max width and height of 128px. What if the image size is 12mb? The image still takes time to get rendered on the page and this is an overhead for your site. When using blog images, the file itself is resized to the dimension that you want physically and that also means that the file size is reduced.