Update links + Fix images

[remibetin]

Resource URL

https://www.w3.org/WAI/resources/

Add a description

Broken images:

• [x] https://www.w3.org/WAI/content-images/wai-std-gl-overview/specs.png
• [ ] https://www.w3.org/WAI/content-images/video.svg

Links to update when "Evaluating Web Accessibility Overview" is moved

• [ ] /content-images/wai-eval-overview/video-thumb-conformance.png
• [ ] /content-images/wai-eval-overview/video-thumb-tools.png
• [ ] /content-images/wai-eval-overview/video-thumb-easy-checks.png
• [ ] /content-images/wai-eval-overview/video-thumb-involving-users.png

Resource Shortname

wai-resources-list