I remember transparency was handled with gifs back then, which had their own problems and limitations.
Alignment was either done via position: absolute or by using a table. The animated background here would be a bit more complicated with a table.
Risk of it breaking with some upgrade, or looking different for some people? As you said, very likely.
So server-side image generation was indeed the best option. And it was a popular and widely solved problem, even in the 90s: visit counters that showed the visits in the shape of an image were super popular.
Alignment was either done via position: absolute or by using a table. The animated background here would be a bit more complicated with a table.
Risk of it breaking with some upgrade, or looking different for some people? As you said, very likely.
So server-side image generation was indeed the best option. And it was a popular and widely solved problem, even in the 90s: visit counters that showed the visits in the shape of an image were super popular.