Zoho Books - uploading company logo squashed

Zoho Books - uploading company logo squashed

I am trying to upload my company logo with the following dimensions - 240 x 240 pixels and a file size of 106Kb. When I look at the logo in my invoices, it is squashed and not the right size. Any idea what is going on? I've tried uploading jpeg and png formats. 

See attached

    Nederlandse Hulpbronnen