Here's how to anchor a graphic:
Notice that if you pause over the small blue square at the upper right corner of a graphic frame, you'll see this tooltip:
Drag to where you want to anchor this graphic. This is the result (with View > Show Text Threading turned on):
Here is the result in a Reflowable EPUB:
You can select the graphic and use Object > Object Export Options to control alignment and spacing. These also can be put into an object style.
Works in most cases but I've already run into one image where the slightest budge of the image throws the text out of its format.
Isn't there a keystroke or command that will accomplish this without having to physically move an already-placed image?
It may not be obvious from the screen shot but you do not have physically move the already placed image. What could is where it's anchored, and the settings in Object > Object Export Options in terms of the EPUB that is produced.
You can't automate it with a keystroke because there is no way to specify the anchoring point except by indicating it in the layout.
Many thanks! I've surrendered reflowing the document and will go forward with it in fixed layout - and deal with issues about links (or lack thereof) in the TOC and the cryptic error message: "Index Page entry not found: 54"