When I add images using Insert => Image Linked to File sometimes the images overlaps the text above in the source file (.scriv). To see the text I have to add 4 “returns.” It looks OK in the output because I have Scrivener handle multiple blank lines so the extra lines don’t show up.
Attached is a screenshot without the returns,
You can get a look like that if the paragraph you are inserting the image into has a fixed height on it. Put the cursor on the image line, and use the Format/Paragraph/Line and Paragraph Settings… menu command. Make sure there are no values set in the Line Height area in the middle. You’ll usually want to use a dynamic line height multiple for image lines (and a multiple of 1.0 at that), and leave spacing to the paragraph padding options at the bottom.
But that setting can be useful if the image is meant to fit on a line and isn’t quite the same size as the line of text around it—more often equations and other forms of inline graphics.