Huh. Uploaded jpegs get corrupted (turned into stripped lines) for some reason.
Okay. I’ll try to upload lower resolution pngs instead, for the embed previews…
Edit: Reason was found! It was my browser (LibreWolf) blocking HTML5 canvas access. See developer’s answer ~ https://discuss.kde.org/t/some-uploaded-jpeg-images-get-corrupted/5572/2?u=waterfall And, this also can be caused by extension (like CanvasBlocker), which is just good to know (was not my case).