[guwu]

Seems as if thumbnail generation is indeed the cause of the problem in my case. After switching the feature off browsing pictures now works at 'normal' speed. Still switching between pictures (~4MB files stored on NAS, 1000Mbit ethernet connection, SMB share) seems a tad slow (compared to my iMac where switching between pictures works without any noticeable lag).

[jgs2n]

I am interested in trying this. How do you switch that off?

Is thumbnail loading a one time process? Is there a way to generate all thumbnails at once (like scanning music to library)?

[NativeCanadian]

Did this work for you? Any other solution?

I am interested in trying this. How do you switch that off?

Is thumbnail loading a one time process? Is there a way to generate all thumbnails at once (like scanning music to library)?

[selectany]

Is thumbnail loading a one time process? Is there a way to generate all thumbnails at once (like scanning music to library)?

I think this would resolve the problem.

I also experienced such a kind of problem.

As workaround: disable thumbnails.