Download UWC to change the size of taskbar buttons & thumbnail previews
W7 Taskbar Tweaker is a free and portable utility for Windows 7, part of the Ultimate Windows Customizer suite. It will let you change the size of taskbar buttons and /or thumbnail previews.
The developer created this application after realizing that the buttons on the taskbar take up too much space unless they are combined, which some may not like to do. Users with large monitors may face the exactly opposite problem, wanting even more space for each taskbar button in order to follow real-time updates some programs display on their taskbar buttons. In both cases this utility will prove useful, to increase or decrease the size of your taskbar buttons and /or previews.
Note that this tweak will not work if icons are set to Always Combine.
Should you wish, you can always restore the default settings by clicking the appropriate button.
Since I wanted more space for each button, I changed the default setting to 260. For the opposite effect, i.e. to decrease the size of each button, the author suggests the use of Small Icons and a size not much more than 30.
If you only want to change the size of your taskbar buttons (not the thumbnail previews) you can just download this simple registry file that will do the trick (2 KB). Check also Taskbar Labels, a nice little utility that will let you have a shortcut key in order to show or remove at will all text beside taksbar icons on Windows 7.