Dave and Nick have reported problems with adding photos to their posts. There is a known problem with Blogger and Internet Explorer that some users get and causes the "choose photos" option to go missing, which the techies at Google are working on, but until it's fixed here are a couple of workarounds -
At this point, most users have stated that they are using Internet
Explorer, so one workaround has been suggested that users try using
Chrome or Firefox until the issue is fixed.
2. Using the Browse button on the HTML side of the post editor works
for the image upload, and then users can click over to the Compose side
to move the image, resize it or add captions. NOTE: You want to do all
the uploading at once because flipping back and forth between Compose
and HTML repeatedly in one post can mess it up at times. (Nick and Dave have used this option but it is somewhat slow).