Cannot cache Img objects?

[rambo-panda]

I accidentally executed an operation to cache the Img object, as shown in the code below. However, I found that even after I deleted the cache and executed clearAllCache, the RSS it occupies remains high.

const cache = new Map();
cache.add(url, await loadImage(url));

// do something
....
...

setInterval(() => {
cache.clear();
clearAllCache();
}, 10000);