then you must have resized them to post them here right? I mean uneveness which is can you see the background? The light blue part and some light purple? You can actually see the pixels differentiated. hmmm.... what i always do with my camera is that I take the same object, with all different sizes and quality but maintaining the same other settings and environment conditions. Use the auyto mode first. So i download to my pc to view them and see which appears to be the best. You can try that too and I am sure you will find the best possible setting for such shots.
Also besides the sizes and quality, if the pics still does not come out good, play with thesettings then. you have to keep on trying cos different objects, different light intensity, speed ....etc will all affect your best setting. So it is a little confusing eh? In conclusion, there is no fixed settings but you have to make lots of shots to get the best out of it. There is one thing good about digital photography, you do not have to spend to develope the pics until you are satisfied with the results.