Amazon API does not provide the highest resolution images. The API image size does not exceed 500 x 500 px. The products imported via the Spreadr app hence have lower quality images than the original images on Amazon.
Moreover, to keep the app prices low, we procure data from low-cost Amazon data vendors. The image quality provided by these vendors is similar to the image quality from Amazon API.
To import high-resolution images, the only way is to use the Spreadr Chrome Extension for pulling products. In 99% of cases, the extension imports the best quality images as available on Amazon.
In case the extension does not provide high-resolution images, then you have to perform an extra step in clicking the main image on the Amazon product page before clicking the Spreadr chrome extension. Video available here.