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I am using Kubuntu 12.04 with Firefox.

Since version 13, a new tab in Firefox displays a mosaic buttons representing the most visited pages as short dials to those pages.

firefox thumbnails

These buttons should be thumbnails, but in my case, there is no thumbnail to be seen in a any of these buttons, nor is there an option to force a thumbnail to be loaded.

How can this be solved?

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The following thread on Mozilla did not help at all: – Benjamin Aug 22 '12 at 15:58

I wish I could tell you for sure that doing "xyz", but unfortunately it seems that these feature does not always work as it should.

It is based on the websites you visit, and thus it updates every time you browse. If you pin a website, it will be updated to match the last view of the website every time you use it (in theory).

The thumbnails are stored in a rather confusing format, in folders numbered "0 to 9", and then from letters "a to f".
Thumbnails folders

These folders contain other folders, and in those folders is where you will find the thumbnails. Since the thumbnails are auto-generated, it seems like there is no way to "fix" missing thumbnails, other than maybe to pin "tiles" that actually have picture rendered.

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Hi Roland, thanks. Pinning the tiles does not seem to force the thumbnail to load either. – Benjamin Aug 22 '12 at 15:54

The thumbnails are now in ~/.cache/mozilla/firefox/*.default/thumbnails. You can try closing Firefox and deleting that directory. See also

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Please, refers to the following link:

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Please also describes the steps along with the link for reference. – tuxtu May 6 '13 at 14:23

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