Uploading an image to a WordPress post has one major flaw.
When I started using WordPress 6 months ago, I couldn't believe that such a well crafted application would have such a poor tool for adding images. I tried and tried with the built in image tool, then gave up and tried a variety of plugins to enable me to add images to my posts.
I have just discovered that "Send to editor" is in fact the solution.
1. You upload your image.
2. You click the image and choose the options you desire.
3. You then click "Send to editor" and it adds the code to the post.
To me, "Send to editor" means "open this image in Photoshop" (or your default image editor). It does not say to me - clicking this button will add the code to the post.
"Send to editor" is a misdescription and I suggest that it is changed to:
"Add to post"
or something like that. It would make much more sense.