Apologies for my numptyness in advance.

I’m trying to upload an image which only allows a maximum of 240kb per image. The image I want to upload has 533kb. Is there a way to reduce the kb count to the required number?

Any solution must be couched in language your granny would understand.

You Ca’n either resize the image – make it fewer pixels. OR
Resave the image at a higher compression (lower quality) rate.

Depends what it is and what software you have.