OK, there are a couple of things to consider when adding an image, namely Alt Tags, Links and Size of your image ...
Step 1: Select the image you wish to insert into the page (if it isn't already selected)
Step 2: Using the far right scroll bar, scroll all the way down to the bottom of the page
Step 3: I usually add an alt tag, which is titled the same as my page. This used to play a part in SEO, but it's not as big a part as it once was. It's just something I tend to do, down to habit. An important thing to remember if you have more than one image, is to give them different alt tags. (An Alt Tag, is a tag used by the search engines to search for images related to specific search terms and is not shown on the image. You can add an optional Caption, which will be displayed underneath your picture once inserted, or adding a description, which is usually shown, only when someone hovers their mouse over your image)
Step 4: I have selected 'Right' for my alignment, as I want my image at the top right of my page.
Step 5: Link To: I have left this as media file, which will just show the picture again, if anyone clicks on it. Selecting None, will make your link not clickable or selecting Custom URL, means you can link your image to either another page on your site, to an affilaite offer, or to someone else's website. Even if I'm linking to another website, I usually select 'None' here, as you can add a link from within the post. And finally ...
Step 6: Size: This was quite a large picture from the uploaded original, so I have selected the Medium Size option for this exercise. Once all your options have been set and the 'Alt Tag' added, click 'Insert Into Post' and your image will be displayed in all it's glory, for the whole world to see :)
Moving on, we'll take a look at the finished article ...