I've just had a look with Chrome & that doesn't display Rob's un-tagged image correctly either...
This leads me to the thought that although we may be using firefox AND have it set up correctly, the vast majority of internet users will not. Therefore when ever the forum resizes an image and removes the tag, the vast majority of users will not see our images as we intended

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It therefore follows that we should upload images so that they are NOT resized. I'm not sure at what point that happens, but I know that with images max 1000px it doesn't but 1100px images are so maybe 1000px is the limit