^^ That's basically it.
Having a whole series of the same picture - irrespective of what it is - duplicated simply to reply to the copies of it immediately above is inefficient, a waste of forum screen space, and has already been the subject of complaints.
Duplicating images will also increase the data required to display the page and this is important for two reasons - not everyone is blessed with a fast Internet connection so more pictures means a slower page load time, and some Internet Service Providers place limits on the amount of data their users are allowed to download. Clearly, forcing them to download the same picture several times - by virtue of it being posted to the forum several times - would be wasting that data allocation.
There's a similar thing - though not so important, data-wise - done with text quotes, where the quote is posted immediately underneath the original before the response. It's much better in these cases to simply post the response because the page is not cluttered with duplicated content and the conversation flows more naturally down the page from one post to the next.
In other words - just use the "Post Reply" button every time, unless it's absolutely necessary to quote something - and when something is quoted, quote only the part the response is intended to address. There's no reason to repost a picture if it's still visible on the page, and neither to endlessly repost an ever-growing stack of quoted-quotes-of-quotes: it just gets difficult to read.
Note that none of these are rules and there will be no sanctions if members don't do these things - it's just basic, good and tidy posting practice - so worth using for that alone.
It's "nicer".
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Giraffe: a ruminant with a view.