Hi Hendrik, don't panic. You can easily post pictures as an attachement here. See just below the text box when posting.
Allowed file types: jpg, gif, png
Restrictions: 5 per post, maximum total size 1024KB, maximum individual size 200KB
Image size should be between 600 and 800 pixels for the long side imho, then choose a matching jpg compression to not exceed the 200 KB limit. Attached pic will be uoloaded when you push the "save" button. See sample. No progresseion bars or so, wait until the page refreshes.
That should help.
Another possibility often choosen here is to upload at flickr and link the desired display size with BBCode, a bit tricky at first sight but works fine. So you can upload full resolution pics if you want and display smaller sizes here.
