The screenshot is from my desktop with wide enough screen on Lemmy web (programming.dev).
The issue is one of scaling.
When I open the image without being resized into the website layout, it has the following visual pattern:
When I zoom out to 50% it looks (almost?) fine
Did you scale the source with ffmpeg? Do you have a visual pattern in your console background? The simplest solution would be to have a solid color as background. The second best to render a small enough size that it does not get resized in the browser.
At 1920x1038, it's very big right now. I'm surprised the font is big enough to be readable. I assume you scaled it up or have a high dpi display resulting in this.
"can not last" and "use when available" are two very different things.
I doubt people felt they wouldn't "last" - as in survive - an hour without internet.