x/website/_content/blog: images should be readable in both light and dark themes

[fflewddur]

It looks like the Go blog now follows the system setting for dark or light mode. For blog posts that include diagrams, this means we have images with light backgrounds that really stand out against the dark page background, and in some cases have transparent backgrounds that break entirely. This might be one section of the site where it makes sense to keep the light theme by default; just wanted to raise this issue in case this behavior was not intended.

As an example, here's a screenshot of last year's survey results, which assumed a light theme:

[cherrymui]

cc @dmitshur

[dmitshur]

Thanks for reporting this Todd. The need for images to handle both light and dark modes applies to content on the entire Go website, including documentation, tutorials, etc. There've been some previous similar reports like #54954, maybe more.

I think this issue is known to @golang/tools-team and it'll prioritized by them as appropriate.

[fflewddur]

That sounds good, thanks Dmitri! If the team decides to keep the current behavior, just let me know so the UX team can update our older developer survey charts.