We recommend that your photo dimensions = 1200px x 500px landscape orientation for the best display. Anything smaller, and you will likely get a pixelated image.
Note: the larger the photo/s, the longer they may take to upload.
There is a viewfinder to help you crop the photo after uploading if you do not have the perfect dimensions. It looks like:
Be sure to see how the listing will look to guests on mobile by clicking on the link under the event name in the editor using a mobile device.