When you add an image into your blog posting within Blogger, the software has a built in default. If someone clicks on the image, it just opens up in a lightbox. Just click on the image below to see what I mean. But before you do, remember to click the cross in the top right hand corner of the lightbox to close the image.
So as you saw, if you did click the image, it essentially opens in the same window, which in turn increases the chances of someone incorrectly closing the page.
One thing you may want your reader to do is go to another location, using the image as a link. To help overcome this problem, I've written a tutorial on my author website explaining how to set up an image with a link when using Blogger. And to prove it works, and to read the tutorial, just click on the image below to be taken to it. You'll also note the link opens a new window.
If you read the tutorial I hope you found it useful.