The issue might occur when uploading an image to the Media Library root folder using the Select Media dialog box. In cases when an Image field already has an image selected, if a user selects the Media Library root as a destination folder, the image is uploaded as a child item of the image that has been selected previously.
Disable the dialog box that is based on SPEAK UI Framework in order to use the old one.
Modify the Sitecore.Speak.Applications.config file (located in the \App_Config\Sitecore\Speak.Applications or the \App_Config\Include folder) as follows:
<overrideXmlControls> <!-- <override with="/sitecore/client/applications/Dialogs/SelectMediaDialog" xmlControl="Sitecore.Shell.Applications.Media.MediaBrowser" /> --> </overrideXmlControls>
Clear the Image field before uploading a new image.
Avoid uploading images to the root folder of the Media Library.