If the "Include Alt Attributes..." is checked, about how much larger will the albums become. Any negative side of doing this?
As the user's manual explains, this adds the entered
title to the ALT tag, or the file name, if there's no
title, so unless you've been using titles to write the Great American Novel, it will add almost nothing to the size of the album. No real downside, but if you're not concerned about SEO, it's just internal page clutter that serves no other function.
https://jefftucker.jalbum.net/skins/neptune/man/neptune_misc.html
Also, is it possible to configure the Meta "description" tag to include Title & Filename using skin variables?
No, that's not possible. You can enter whatever text you want for the meta description tag. It's then used for every page. It's not reevaluated for each folder, so there's no point in the album build at which variable text can be substituted. The meta description text is cleaned up when the album build begins (to make sure there aren't things like HTML tags buried in it, which are not allowed), but at that point, it's a fixed text string.
