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In Nautilus when I'm browsing my image files, how do I make the thumbnail preview images larger? Or for that matter, the folders themselves are kind of on the small side too.
I'm not on MATE but I believe in Nautilus in the top right hand corner there is a percentage button, if you use this you can make them bigger or smaller.
Nautilus is Nautilus no matter what UI it is running in. If you click edit then preferences you can set the default preferences that you like. ctrl+1, 2, and 3 keys toggle the window view, and ctrl+ +, or - adjust the zoom. ctrl+ 0 resets the zoom to default.