Images uploaded into Zoho Writer document are blurry

We create a document via Zoho Writer mail merge and then add in some images unique to the specific client.
These are clear snapshots of tables and graphs we have created in a different tool.
But once they get uploaded into Zoho Writer they are pixelated/slightly blurry.
How do I fix this as this isn't the quality I want for our client documents?

Thanks in advance for your help.