You can find options for image sizes in the eyeQ Web API Reference Documentation https://developer.gracenote.com/sites/default/files/eyeq-webapi-ref.pdf
The image sizes available are
THUMBNAIL (75) SMALL (170) MEDIUM (450) LARGE (720) XLARGE (1080)
(Note, all dimensions are max size - some images are not square)
You can select one or more image sizes through the IMAGE_SIZE option, e.g.:
<OPTION>
<PARAMETER>IMAGE_SIZE</PARAMETER>
<VALUE>XLARGE,SMALL</VALUE>
</OPTION>