XnView Software

Alright, I had enabled the high quality resizer in XnViewMP. With this turned off opening images to fullscreen isn't slower anymore. Sorry, my fault.
However, lo load thumbnails of the 400 photos XnViewMP takes about 15 seconds and XnView classic about 3 seconds (according to the progress bar at ...

Files are of 4 MiB size (about 8 megapixels) at least. Folders contain up to 400 photos. I made a 'fair' comparison by turning off database cache in both MP and classic version. By turning it on loading thumbnails is faster of course. I didn't change the default settings for embedded thumbnails

xnview wrote:Which format?

The speed difference is most significant for large jpeg photos

xnview wrote:You means thumbnails?

Yes, thumbnails is the correct word here

opening pictures from Windows explorer or from the XnView browser is more or less equal. But also loading sub-dirs and previews from directories is faster in classic XnView

yes, I used v0.51

yilusheji wrote:open picture too slowly

I can confirm this. The classic XnView is much faster, tested on Win XP using a slightly outdated PC with old Pentium 4 CPU