Unable to upload/display images

[omltcat]

Within a card, I have tried:

• Click "Image (Ctrl-G)" - "Browse" or drag/paste in a image > I can see image preview now > Click "Add image"
  • Result: card is immediately closed, and nothing is added to the content
• Click "Image (Ctrl-G)" - "Browse" or drag in a image > I can see image preview now > Drag this preview image into content below
  • Result: getting a super long string starting with data:image, but not displayed as a image in rich text mode.

The only way I can add image now is by linking from another website. But on the server I can see that image added above are indeed uploaded to config/images. It just can't be displayed, or am I doing things wrong?