iphone storage whatsapp storage taking too much storage

i have a problem bothering me a lot my whatsapp storage says it has taken 1.8 GB of storage and in settings app whatsapp is taken 10 GB ! even if its back up data it doesn’t reach 2 GB really frustrating I couldn’t find a solution i have tried taking so many conversations deleting them i just kept the important one and it’s still taking 10 GB on iPhone I don’t know why if anyone can help me it would be much appreciated