I have taken a crisp screen shot for a tutorial and want to edit it in Affinity Designer. But when I open the png in Affinity the image quality is noticeably degraded. If I upload straight to Wordpress the quality is even worse. The image size is 963 × 843 and the width of the area I'm placing it on my blog is 780. (If I resize the image down to 780 and upload to WP the quality is worse than leaving it at 963 ???)
I don't understand why both Affinity and WP are degrading the quality of the image. I've attached a screen shot of the original image open in Preview next to the same image opened in Affinity (however screen grabbing this example shows a bit lower quality than I'm seeing in real life (why???) - but it's still good enough to show the quality loss in Affinity vs the original.