Thumbnail cache are a trade-off. On the upside, they speed up image browsing. On the downside, they use storage space and add clutter. By design, Windows Explorer caches them inside the same folder where the images are located, in a single system file, Thumbs.db. It also has a simple option to disable caching.
Today I found out that in Ubuntu there is a ~/.thumbnails folder in each user’s home folder. This is in my opinion a very bad design decision. Consider the following scenario:
I have some sensitive images on media. I am on the road and I use a guest account on a third party’s computer to access a file on that media. Thumbnails are generated and left behind on the third party computer to be harvested! I wonder how many users are aware of this potential security risk, and if there is a way to prevent it.