According to the article text:
A key driver behind the success of Chinese apps is that they have integrated e-commerce into their platforms, blending entertainment and networking with sales to monetize their famously addictive algorithms, according to Chinese social media experts and marketing firms.
You can cap maximum image upload size that lemmy instances will host with pict-rs, and the limit varies by instance, as admins have chosen different settings.
It looks like currently, lemmy doesn’t tell clients about the limit ahead of time, just fails the upload attempt if the image exceeds the instance limit:
https://github.com/LemmyNet/lemmy/issues/5322