In previous Mac OS versions (<10.9) I was able to change the images' thumbnails in the finder by zooming or unzooming with the trackpad. Now that I run on Mavericks, I can't find a way to do it. Does anyone know a trick for that ?
In any folder or window (including Desktop) simply press : CMD+J
If the Status Bar is showing (View > Show Status Bar), then you can use the slider in the bottom-right corner to adjust the thumbnail zoom.
In list view, you can't get your icons any bigger than the larger of the two sizes available in the View Options choices; it's been a problem for when trying to review (most) images since the thumbnail icons came out.