Until last week I was thinking that increasing the taskbar thumbnail window size is not possible natively in Windows 7 (and Windows Vista). Well! Windows 7 supports the ability to increase the thumbnail preview size natively, through registry edits which I’m covering in this article.
This is how the taskbar thumbnail preview window appeared prior to applying the following edit.

Make the Taskbar Thumbnail Preview Bigger in Windows 7
1. Launch Regedit.exe and navigate to the following location:
2. Create a DWORD value named MinThumbSizePx
3. Double-click MinThumbSizePx and set its value data accordingly. I set it to 350 (Decimal) for this example.

4. Exit the Registry Editor.
5. Logoff and login back.
And you can see below that the taskbar thumbnails has grown bigger in size.

Additional Information
Similarly, you can tweak the following registry values under the "Taskband" registry branch, and customize the taskbar thumbnail previews as you need. Here is the entire list:
- NumThumbnails
- MinThumbSizePx
- MaxThumbSizePx
- TextHeightPx
- TopMarginPx
- LeftMarginPx
- RightMarginPx
- BottomMarginPx
- ThumbSpacingXPx
- ThumbSpacingYPx
Editor’s Note: Hoping to write an program to customize Windows 7 Taskbar Thumbnails based on the above registry edit. In Windows Vista, the feature was made available by a nice little program called Vista Thumbnail Sizer by Andreas Verhoeven, which was announced by the How-To Geek Website.
Related Posts
- How to Disable Taskbar Thumbnail Preview in Windows 7
- How to Adjust Aero Peek Desktop Preview Mouse Hover Delay in Windows 7
- Enable or Disable Thumbnail Preview for PDF Files
- How to Fix Image Thumbnails Not Displayed in Windows 7 and Vista?
- Enable Thumbnail Support for .NEF File Type in Vista
If you enjoyed this post, make sure you subscribe to our RSS feed! We feature Tips, Troubleshooting information, Scripts and Utilities for Microsoft Windows Operating Systems!
Prefer an E-mail subscription?




[...] If you’d prefer to change the settings manually without using a dedicated application, here’s a list of the registry changes you can make to accomplish this by [...]
will that ever be possible for the thumbsize of the previews in alt+tab ???
@Ramesh Srinivasan : it worked , thanks a lot !
Someone finally figured it out – Great work! I was considering writing a shell hook to do the same (like Ave’s tool for Vista), thinking there weren’t any registry keys that would let me do it.
Once again, brilliant work!
Well some of the values are obvious, like Left, Right, Bottom or TopMarginPx and Thumb Spacing but wht about TextHeightPx?
Merely restarting Explorer is enough, logoff isn’t necessary. I knew about the Vista trick but didn’t know about the Windows 7 since the registry keys and values are totally different? How do you discover these reg values? Registry monitoring? Can you explain what the other registry values are for?
@Abdullah: For Vista, see http://www.howtogeek.com/howto/windows-vista/increase-size-of-windows-vista-taskbar-previews/
what about vista ? is there anyway to enlarge the thumbnails ?
Can you give more details on the following options:
ThumbSpacingXPx
ThumbSpacingYPx
NumThumbnails
TextHeightPx