[scribus] Image sharpness

[John Jason Jordan]

Scribus 1.5.3 on Xubuntu 16.04, from AppImage

I am having a devil of a time with a photo to be used on one side of a
business card (with bleed). On-screen the image looks fine in the GIMP,
and the exports from the GIMP as EPS, JPG, TIFF, PNG and PSD all look
fine when I open them in any of various image viewers, and they also
print fine as well. But when I load any of them into an image frame in
Scribus the image is blurry on-screen, and prints blurry as well. I
export to PDF and the image is blurry in the PDF on-screen, and it
prints blurry as well.

I've looked all over Scribus and found no solutions. What is Scribus
doing to my photo and how can I make it behave?