Images in Control Panel not loading

Hello, I'm completely new to statamic and playing around a bit with the Redwood Demo. I installed statamic 2.10.5 on Windows 10 with WAMP in a subdirectory and followed the instructions in the docs (changed path for $site_root and in system.yaml with a trailing Slash). In the Templates I used link-Tags to output correct image-Urls. After that, the images were displayed correctly.

I have found that there are images that I can not affect and that can not be loaded., for example preview images in a blog post in the Control Panel. I don't know if I'm doing something wrong or it's a core-issue.

here's the JSON-Response from http://localhost/statamic/cp/assets/get. "permalink"-Value is correct, but "url"-Value should be "/statamic/assets/desert.jpg"

[
  {
    "thumbnail": "http://localhost/statamic/cp/assets/thumbnails/bWFpbjo6ZGVzZXJ0LmpwZw==/small",
    "toenail": "http://localhost/statamic/cp/assets/thumbnails/bWFpbjo6ZGVzZXJ0LmpwZw==/large",
    "id": "main::desert.jpg",
    "title": null,
    "url": "/assets/desert.jpg",
    "permalink": "http://localhost/statamic/assets/desert.jpg",
    "path": "desert.jpg",
    "filename": "desert",
    "basename": "desert.jpg",
    "extension": "jpg",
    "is_asset": true,
    "is_audio": false,
    "is_previewable": false,
    "is_image": true,
    "is_video": false,
    "fieldset": "asset",
    "edit_url": "http://localhost/statamic/cp/assets/main/desert.jpg",
    "container": "main",
    "folder": ".",
    "size": "670.09 KB",
    "size_bytes": 686174,
    "size_kilobytes": "670.09",
    "size_megabytes": "0.65",
    "size_gigabytes": "0.00",
    "size_b": 686174,
    "size_kb": "670.09",
    "size_mb": "0.65",
    "size_gb": "0.00",
    "last_modified": "September 14th, 2018",
    "last_modified_timestamp": 1536949685,
    "last_modified_instance": {
      "date": "2018-09-14 18:28:05.000000",
      "timezone_type": 3,
      "timezone": "UTC"
    },
    "focus": "50-50",
    "focus_css": "50% 50%"
  }
]

Thanks for your Help!