If anyone on the web should know why this is important to fix, it should be this organization. There was another report about this in January of this year, perhaps you should add some testing or something?
It happens when I go to the automated welcome message that I got when I first logged in:
https://community.letsencrypt.org/t/welcome-to-lets-encrypt-community-support/17970?source_topic_id=17982
Iβm using debian firefox 46.0.1-1+b1.
This is in the console:
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/topic-list-select-areas-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/topic-list-select-areas-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/progress-bar-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/progress-bar-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/reply-post-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/reply-post-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/quote-reply-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/quote-reply-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/username-completion-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/username-completion-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/emoji-completion-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/emoji-completion-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/link-oneboxing-animation.gifβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/link-oneboxing-animation.gifβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/like-link-flag-bookmark-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/like-link-flag-bookmark-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/notification-panel-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/notification-panel-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/topics-new-unread-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/topics-new-unread-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://community.letsencrypt.org/images/welcome/topic-notification-control-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttps://community.letsencrypt.org/images/welcome/topic-notification-control-2x.pngβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://ecx.images-amazon.com/images/I/21Kga0u-h8L.SY400.jpgβ on a secure page[Learn More] ember_jquery-c9524b48466ee05bcf3f9ddaf05405387eb17017e61e90e76628f989db37eb4e.js:1:2317
Loading mixed (insecure) display content βhttp://ecx.images-amazon.com/images/I/21Kga0u-h8L.SY400.jpgβ on a secure page[Learn More] 8523
GET
http://ecx.images-amazon.com/images/I/21Kga0u-h8L.SY400.jpg [Mixed Content]
[HTTP/1.1 200 OK 166ms]