OK, looks like the issue is just contained to get involved pages:

```
(kitsune)[rlr (master) kitsune]$ git grep '{{ MEDIA_URL }}/'
apps/landings/templates/landings/get-involved-aoa.html:        <img src="{{ MEDIA_URL }}/img/gi-visual-aoa.png" alt="">
apps/landings/templates/landings/get-involved-kb.html:      <img src="{{ MEDIA_URL }}/img/gi-visual-kb.png" alt="">
apps/landings/templates/landings/get-involved-l10n.html:      <img src="{{ MEDIA_URL }}/img/gi-visual-l10n.png" alt="">
apps/landings/templates/landings/get-involved-questions.html:      <img src="{{ MEDIA_URL }}/img/gi-visual-questions.png" alt="">
apps/landings/templates/landings/get-involved.html:      <img class="hero-butler" src="{{ MEDIA_URL }}/img/gi-hero-butler.png" alt="">
apps/landings/templates/landings/get-involved.html:    <div class="grid_8"><img class="moz-heroes" src="{{ MEDIA_URL }}/img/moz-heroes.jpg" alt=""></div>
```