Did I understand correctly that group image upload fails when you attempt to add an image while creating a new group, but it works when you add an image to an existing group? And this happened with every group?

Not quite.  The group image upload doesn't give me any error message, but the image doesn't display at all, whether it's a new group or an existing group.

Please check whether the image gets uploaded to the data directory.

You may have some javascript errors in your site. That may be the reason for why avatar cropping is failing, Please check your console.

Sounds like a javascript error, a link should be making an ajax request but if js is broken it's sending you to the href instead.  The href is an ajax endpoint which isn't supposed to be viewed directly, it only responds to ajax headers.

Check your console log for js errors.

Howdy again!

I checked the log for errors, and this is what came up, repeatedly:

TypeError: httpChannel.notificationCallbacks is null

The plugin itself is trying to redirect me to ajax/view/forms/profile_manager/type, which doesn't exist.  I've crawled through every logical file trying to figure out where that link is coming from, and I can't find it.  Of course, there's a very real possibility that I've gone off on an unrelated tangent, as I know just enough about what I'm doing to be dangerous.  Barely.

In short, I'm confused again.  And once again, thank you so much for the time you've given me.

That url likely does exist, but it is only accessible via an ajax call (that is enforced by the ajax pagehandler).

Likely the source of the issue is that TypeError, which may not be related to profile manager at all, but if js dies with an error then any other js on the page will be affected.

I'm going to sound like a total noob here, but my current theme's start.php doesn't call for a favicon at all, and yet the Elgg standard one still appears.  I tried simply replacing the graphics file with the new one, and that got me nowhere.

Is there another file that might call for the favicon?

Thanks!

Replacing the file should work (probably a browser caching issue, I know Chrome is particularly bad for holding onto favicons even after clearing caches).  That's not the recommended way though as that's considered modifying core.

http://learn.elgg.org/en/2.0/guides/dont-modify-core.html

What I linked above is the correct way to change them - register a handler for the 'page', 'head' plugin hook, then change the url of where the new image file can be found.  It is a bit more complicated than just replacing the file, but if you're going to be doing any kind of customizations using plugin hooks is something you should learn anyway.

http://learn.elgg.org/en/2.0/design/events.html#plugin-hooks

Now we're cooking with gas!  I'm looking at my shiny new favicon in another tab as we speak!

Thanks very much for all your help!