Featured images pixelated in Flipboard

Hi! I found that when I add my feed to Flipboard, it pulls each post’s Featured Image at a significantly reduced resolution, making the image look visibly pixelated. Other than that the plugin appears to work as advertised!

Any suggestions? All my features images are high-res, all are 2048px on the long side.

https://www.ads-software.com/extend/plugins/sb-rss-feed-plus/