Jpeg compression sometimes too heavy

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The jpeg compression applied to images for the medium and large sizes is normally ok, but sometimes it's too harsh and ruins a good picture. Could you tweek the settings a tad in the right direction? Or allow user to request a slightly better representation?
Here's one example: http://www.expono.com/go/photo/209824...
I know I've seen it in a few of my own too, but this made me remember to post a request about it.