To edit your post and add an image...(skip # 1 if creating your post initially)
1. click on the yellow pencil icon bottom right of post next to the comments link
2. where it says 'font' go to the right… 3rd to last icon, if you mouse over it, it will say 'add image' click on it
3. click 'browse' (as many times the number of images you want to post) to find the image/s in your computer or from the web, and click 'open' after finding image
4. 'choose layout' for image placement (left, center, right) and image size (small, medium, large)
5. click UPLOAD IMAGE
If it is your first time to post an image, click on the box 'I accept the terms of service'
Go to Blogger FAQ for more help on>> Posting and editing