I am no longer able to post images. The image upload tool have been broken for some time. For a short time, I was able to use the old interface to upload images successfully. After they retired the old interface completely, I was able to post images indirectly through Picasaweb. Not the Google Plus Photos tool, which seems inferior in every way to Picasa. (You can use the 'noredirect=1' flag when accessing Picasaweb to not get redirected to Google Plus.) Even though it was a bit cumbersome if I had to post several images, I could make it work. They must have changed something in the Blogger API, though, and failed to update Picasa, because I can no longer post images that way. I'm not sure what else to do and may have to switch blogger platform.