Is anything being done to address user's lost avatars? Avatars are a bit like signatures. I don't want a new pink avatar thanks very much; I want the original green one I had for my first two years on the site. What's being done about this problem?
At @Araucaria's request I'll repost an answer that I originally wrote here:
Can I get my other icon back or will I be stuck with this new one?
Maybe. If you've been using any Stack Exchange site long enough that you've grown attached to your identicon, there's a good chance that it's cached or archived somewhere even if you don't have it yourself.
The tool that worked best for me was Internet Archive's Wayback Machine. I used it like this:
Navigate to your profile page on your favorite Stack Exchange site. This is the page with the large version of your identicon (even though it's the wrong one). Copy the URL for your profile page. The URL will be of the form: http://site.com/users/youruserid/yourusername?tab=profile
Paste that URL into the Wayback Machine and cross your fingers that there's a copy. You'll likely get a calendar showing the various dates on which your profile page has been archived. Click one of the dates and see if your old identicon is there. If yes, download the image.
Go back to your profile page (the current one) on your favorite Stack Exchange site. Click the identicon to edit it, and upload the image that you just saved. Click the Save button at the bottom of the page when you're done.
An MSE question from 20 August identified this as a problem with Gravatar. It's not a Stack Exchange problem: their provider is experiencing difficulties.
There is nothing stopping you generating your own Gravatar-like image — or even something completely different like mine — and uploading it as a custom avatar. That avoids Gravatar and their difficulties altogether.
However, I'm not sure how you can recover your green icon in order to use it in your profile. You may be able to find it if you search for your posts in the Internet Archive.