Ed is correct that I was looking for technical not aesthetic input. Your eyes are better than mine - I had to look up "pixelation" and now think I see it in the flower but not the background, and still am not sure what is meant by (and can't see )"jpeg artefacts". Could you help me by pointing out these issues more directly?
Here is another image taken about the same time but with less sun. I had not submitted this one because I thought the focus not so good. This is the unadjusted RAW saved as jpg with minimum compresion consistent with maximum file size for the site. Do the problems persist? is the light better?
Actually, I find this rather bland but value your opinions nevertheless.
Thanks for your input.
jpeg is a lossy image compression algorithm. It leaves out information wich is not important to the human eye first, thereby enabling bigger compression. The more you compress, the more visible the loss. To make it obvious, crank up your quality slider all the way down, then you will clearly see the artifacts around edges, and the blocky artifacts in smooth areas wich are characteristic for jpeg. Once you know what to look at its obvious. In your first image its quite visible. The new image on the other hand is quite soft as you say and for me not as interesting as the first. (Ok I think the first is also not that spectacular, it is "just" a snapshot of a flower, of a nice flower that is.) The jpeg quality here in the last one is fine. Generally I go for say 80-90% jpeg quality when submitting for web.