I'm afraid I can't give a definitive answer to your question at present, tim - posting a bit of site furniture which appears in every post at some point in another post is a rather arcane matter. I'll look into it further. It may be the image was the wrong size. It may be screenshots can't be used as an attachments. It may be there's something wrong with the attachment.
Possibly posting a picture of a post is potentially prevented by the software considering quotation is quite the quickest and most regular way of referencing another post.
As a more general observation, if people wish to post images I'd always recommend using the "Img" button rather than uploading a file as an attachment.
Thanks, but I think in this case you may be mistaken - I use that facility all the time (well, frequently) in exactly the same way, so it can't be at this end. I post exclusively screenshots, as I don't know any other method. I don't know about the Img button though - I'm using a mac if that makes a difference? That might be a great tip for the future, thanks.
In fact I'll try it now, with the image I was gonna upload... let's see! (Touches blue paper and retires...)
Eh? How does that work?
EDIT - I can see it didn't. For what it's worth, the image I was gonna upload was really small, a LOT smaller than the stated maximum - I'm quite used to posting pics here without a problem, but often have to make them smaller, not so in this case.... Heck, I don't really mind but it is odd.