When i mention pixel dimensions, i'm referring to how things should look on a 1024x768 screen.
It's fine if things take up more pixels on larger screens, but that's an entirely different issue.
...But the icons on the sidepanel are just too small compared to the text. I don't see a reason why the icons can't be a little larger than the text. ... Bascly what I'm saying is, that the relationship isn't right. A letter or number might read at this size, but an icon hardly does.
At any reasonable hight the air-brushy treatment will hurt the "legibility" of the icon.
...I don't believe, you can read the meaning of those icons as they were previously and at a size like 13x13. You will have to learn the meaning anyway(using tool tips). And what then counts, is the ability to remember and distinguish the icons. This is so much easier having colorful, shiny, 'airbrushy' icons than tiny, dull monocolored icons. Putting color in there, I can even put more information in there, than one can with graphical, absract shapes.
By "legibility" i don't mean that the user magically knows what the icons represents. The user will have to learn the meaning, (or check tooltips) no matter what the size.
A "legible" i mean the forms and shapes are distinct and easy to recognize. My complaint with the airbrushing technique used here blurs edges, makes form less distinct.
Look at any professional favicon, or the smilies in this forum, or small element of your OS's UI.
BTW, How many hundreds of Favicons can you easily differntiate at 16x16? It's quite possible to make a distinct image at that size or a few pixels smaller.
There may be be gradation in value, but you find relatively few colors, and the major shapes are distinct
. Simply adding more colors and more variations of lightness does not make an icon better. The distinctness of the primary forms is most important.