The only question I have so far asked really required an image to illustrate the point. Another user with sufficient rep kindly added the image to the original question with an edit. I now have further info to provide but I cannot edit the original question without losing the image that was so kindly attached for me.
I have compromised by adding the extra detail in a comment but this is not very satisfactory as it is easy to skim over the comments.
It would be much better if the an image, once included in a question, was allowed to remain when a question is edited by a low-rep bum like myself, providing (of course) its url is unchanged.