Not able to embed images in notes

Thanks again, and there are no silly questions! People do lots of dumb stuff (myself very much included). I now use a dedicated Attachments folder, but I have also some leftover images in other folders. None of them open or embed. I use autocomplete. This is not different from how I worked with images before, so I also reckon/hope that’s not an issue. My first thought was about permissions as well (please note that I’m really not computer savvy), but I see no issue in the file/folder Properties in Win Explorer, and also I can’t understand why the files in the same location and with same permissions - but PDFs - open and embed just fine.
I’ve tried your suggestion with drag & drop - no difference.
I shall update the Obsidian to the latest installer. As a workaround, I’ll see if I can set up local vaults for all machines, as this seems to fix the issue.