Well, my images are referenced like this:
<img alt="" src="../Images/logo.gif" width="10%" />
Which seems very different from what you are showing.
To add an image, I right-click on the Images folder and choose Add Existing Files. Then I browse around my computer and click on the desired image. It doesn't have to be in the same folder as the epub.
Note that if you are actually publishing a Kindle edition, there is no need to convert to mobi format. (Indeed that may be counterproductive.) The KDP (Kindle Direct Publishing) platform has no problem with epubs.