If the logo isn't in an anchor, I would treat it as presentation. Thus, it has no business in an IMG tag and would/should be applied via the CSS.
The logo's for the social media links kind of get the same thing. They are a presentational affectation for the site names, so rather than confuse screen readers, braille readers, and the like hoping that magically ALT text does it's job.
Also multiple NAV on a page seems to make things really hard to navigate on my braille reader and non-apple screen readers.
I'd have that code something more like
<footer>
<hr>
<address>...</address>
<ul class="socialMenu">
<li class="facebook"><a href="#"><span>Facebook</span></a></li>
<li class="instagram"><a href="#"><span>Instagram</span></a></li>
</ul>
<ul class="legal">
<li><a href="#">Privacy</a></li>
<li><a href="#">Imprint</a></li>
</ul>
</footer>
Where the HR provides a landing / subject break for legacy UA's, and the span would be absolute positioned off-screen with generated content with webfonts or SVG backgrounds used to apply the icons. None of those images qualify enough as content to be in the markup.
Fun part is you could use the span as styled tooltips on hover / focus. See what I did at the bottom of this rewrite of one of FailwindUI's templates:
https://cutcodedown.com/for_others/medium_articles/failwindUI/resalient/resalientFontIcons/resalient.fontIcons.html