The photograph isn't relevant to the topic, but it is on the phone, so I can use it. It appears that Picasa isn't directly accessible. It places the photo after the text even though it was the first thing I did for this post.
The Blogger app shows five formatting buttons: a B for bold; an I for Italic; a link for creating a link that requires selecting text; a camera that opens the phone's camera; and an obvious photo graphic for inserting a photo. I don't see any placement or sizing options.
As far as SEO goes, I can create labels but there's no obvious way to create a description meta tags, nor can I add title or alt text to the photo.
So, before I hit the publish button I'd say it's not fully functional. At least the Blogger app from Google is free, and for a quick post to edit later, or for writing a draft I'd say it is definitely okay but not superior.