When browsing a directory of images, on every image switch gwenview currently (19.12.3) blacks out the screen, shows a loading icon in the middle of the frame, and then displays the image (presumably because it is loading, preparing to draw, etc.)

It would be great if gwenview could wait to make any changes on the screen until the image is ready to be displayed and then instantaneously update the image. (Apparently this was fixed in 18.08, but was changed back to its current state at some point; see bug #403162)

There doesn't seem to be any UX value to changing the screen to black while the image loads. For viewing directories of images that are, e.g. frames in an animation or time lapse, it's nice to be able to smoothly see the difference between two images without a disturbing visual interruption when switching. Flicker-free changing also generally improves the feel of browsing unrelated images. (I doubt there is really a medical argument re: seizures, but it might be relevant to someone that wants to scroll through many bright images?)

When/if this change is made, the loading icon should also be moved from the image frame and on to the toolbar, for the same reason: best to avoid disturbing visual changes to the image frame whenever possible. (Having the loading icon remain in the image frame would somewhat defeat the point of removing the black flicker, IMO.)

I will file a separate bug for pre-bufferring of images to make switching faster.

Thanks for considering it!