[pandog]

I think a high definition photo taken on a recent phone takes up an awful lot more device memory than a "big number of chats"

[SonOfLilit]

Yeah, but Whatsapp chats tend to be full of those... and videos.

[akx]

(On Android), if you don't care about the (old) WhatsApp media, just delete it from your phone. It's all just loose files in `/storage/android/data/com.whatsapp` (or thereabouts). The text content of the chats will remain available.

[lukan]

Whatsapp automatically resizes them (in standard settings)

But it still gets big.