Sorry you can’t post pictures directly, Stoffbeutel.
The photos need to be on a picture hosting website such as flickr.com. This is the one I used to use, until they started charging for hosting more than a small number of photos (which I had long since passed).
You could try Instagram, imgur.com, or add them to add morsbags.com facebook page to share with other morsbaggers. I googled “photo hosting sites for forums” and found a variety of suggestions, some of which want you to join.