You just have to get your cursor above the image and then you can’t start typing. Greg’s method works but is not nescessary.
You can use the arrow keys on your keyboard to get “in front of” the image if you are on a computer. If you are on a mobile device it’s a little trickier. On iOS devices just click and hold on top of the cursor for a second or two and you get a magnifying glass zoomie thing (pardon the technical terminology) which you can move before (not above) the photo. Keep in mind the there is no “above” the photo if you place before typing anything because it is the first object in the composition window.