If you're a regular blog reader, you've probably noticed that Blogger-hosted blogs now display blog photographs in a new way. It's called "Lightbox" and photos appear against a black overlay accompanied by thumbnails; the images are smaller that they used to be and there's no longer the extra click-to-enlarge-even-more facility. Irritating? Along with many other bloggers including My Ancestors and Me, I think it is.
If your blog is hosted by Blogger, it's easy enough to switch Lightbox off and revert to Blogger's previous way of displaying images. From the Blogger dashboard, click on the Settings tab. From the Settings page, click on Formatting then cursor down to Show images with Lightbox, change the box alongside to read No. Click on Save Settings at the bottom of the page and you're done.