To delete media files from your music, photos or videos tab, you should:
Step 1. Click 'Edit EPK' in the top righthand corner menu.
Step 2. Select the media tab you're interested in on the lefthand side.
Step 3. Select the files to be deleted and hit 'delete selected.'
Please note that if you are looking to delete files from your social media connected files, you need to remove them from their originating source such as Spotify, Instagram or Rdio.