Yes you can.
The recommended size for your logo is 320px x 320px. If your logo is not square please make the logo no wider than 320px.
To change the logo image for your product page please go to:
Settings->eBay Australia->Product Template->Product listing template->Your Logo-> Add your logo URL:
In this box, add the URL of the logo image you wish to use and click update: ( please note this must use a secure URL https to comply with eBays requirements. )
You will need to update market place to ensure the new logo is used.