[eog] Add instruction page to remove pictures

[Jiro Matsuzawa <jmatsuzawa gnome org>]

Hi documentation team,

I've written a help page to instruct to remove pictures on eog. I
filed it as Bug 707383 [1]. Could you please review it?

Thanks in advance.

[1] https://bugzilla.gnome.org/show_bug.cgi?id=707383


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Jiro Matsuzawa
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