STEREO-A/EUVI images (top: 284 Å, bottom: 304 Å) showing the coronal hole and the flaring regions during the SEP event on 17 July 2014. The left panels show a pre-event image, the middle panels show snapshots close to the event peak, and the right panels show the ratio between the two images to highlight the differences. The boxes indicate regions in which changes are observed. Region [1] shows the strongest flare brightening and produced a very long jet (see Fig. 6).