Filepicker: broken previews when streams are used

[u07]

As the docs say, we can use theme:// in filepicker. But it does not work as intended.

[pamtbaau]

@u07, Please do not use images to explain an issue (see Stackoverflow for reasons) and preferably provide:

• a verbal explanation of the problem. "But it does not work as intended." does not quite describe the problem.
• a short reproducible case showing the issue

Using a fresh install of Grav+Admin v1.7.43, I do not find anything that is "not working as intended".

My setup:

• Fresh install of latest Grav+Admin v1.7.43
• Added a filepicker field to blueprint /user/themes/quark/blueprints/default.yaml

  header.picked_image:
    type: filepicker
    folder: 'theme://images'
    label: Select a file
    preview_images: true
    accept:
      - .png
      - .jpg
  

• Added extra image windows background.jpg to folder /user/themes/quark/images
• Admin shows the following field:
  
• When picking a file and saving the page, the frontmatter of the page looks as follows:

  ---
  title: Typography
  picked_image: 'windows background.jpg'
  ---
  

[u07]

@pamtbaau, thanks for taking a look into this issue. As you succeeded getting previews working, I should conclude that some details are important for reproducing this.

For now, the only difference I see is that you are modifying a theme blueprint, while I was working with a flex objects blueprint. There is one named Contacts, coming with Grav as an example.

I'll provide a step by step later because of vacation, no pc here.

[pamtbaau]

@u07, Can't reproduce the issue either using flex-objects...

My setup:

• Fresh install of latest Grav+Admin v1.7.43
• In Admin edit config of plugin Flex-Objects and enable 'Contact' directory
• Copied folder /user/plugins/flex-objects/data/flex-objects to folder /user/data
• Copied file /user/plugins/flex-objects/blueprints/flex-objects/contacts.yaml to /user/blueprints/flex-objects/contacts.yaml
• Added a filepicker field to form section in blueprint /user/blueprints/flex-objects/contacts.yaml

  picked_image:
    type: filepicker
    folder: 'theme://images'
    label: Select a file
    preview_images: true
    accept:
      - .png
      - .jpg
  

• Added extra image windows background.jpg to folder /user/themes/quark/images
• Admin shows the following field when editing a Contact flex-object
  
• When picking a file and saving the contact, the contact in /user/data/flex-objects/contacts.json looks as follows:

    "gizwsvkyo5xtms2s": {
        "published": true,
        "first_name": "David",
        "last_name": "Tucker",
        "email": "dtucker0@tripod.com",
        "website": "http:\/\/flavors.me",
        "tags": [
            "Puce",
            "Teal"
        ],
        "picked_image": "windows background.jpg"
    },