No. There is BlueGriffon which is built using Gecko. I don't know that it provides any advantages. The developers use whatever editor they are comfortable with. Ranging from vim or emacs to sublime text, vs code or atom to visual studio.
My first thought is to install downthemall, export your bookmarks as an HTML file, view it directly, then use downthemall to download the pics from it.
If the file is too big and unruly, you could edit it in a text editor or something like BlueGriffon. to isolate just the links you're concerned with.
~~BlueGriffon~~ [Standalone, not online/extension]
You can edit files directly on GitHub, if you're using that.
No, you can still sell licenses like [BlueGriffon](http://bluegriffon.org/) does, it all depends on the approach you take. You should probably try to get a bit more informed instead of imposing this mindset of yours that is "everything open-source is fucking communism", since it's clear to me that either you don't know shit or you're a low-level troll. Probably the latter regarding the other comments you made here.
Try Blue Griffon. It's a WYSIWYG editor made by the co-chair of the W3C's CSS Working group. I.e. it's made by someone who actually cares about the output that is produced, which is basically the opposite of Dreamweaver. It's not guaranteed that it'll fit all your needs or that you'll be able to adjust to it easily since its UI is quite different to Dreamweaver and typical Mac apps, but give it a go; can't hurt: it's free (and open source).
Traditionally the best tool for easy web pages is Adobe Dreamweaver but as you want free: http://bluegriffon.org/
But you will need to find a web host (This can be had for a couple bucks a month) and register a domain name (This can be had for $6/year).
Well if you start minimalist there's just less to go wrong. That's my theory on starting anyway ha!
I would recommend sticking with notepad++ or my personal favorite sublimetext.
BlueGriffon is a WYSIWYG editor posted here a while ago but I can't really comment on it. I've always felt sticking with code is the only way too understand what you're doing though.