Turned out that default settings in PCManFM-QT are generating thumbs only for files smaller than 4 MB.
Which nowadays is a very silly default as normal photos taken by smartphones are commonly larger. I can try to get statistics if someone doubts about that.
I also think that it is fairly safe assumption that people expect thumbnails for photos.
Not surprised. Upstream tends to be very selective when it comes to changes.
They tend to value things that make sense for a wide variety of types of users (whether they be maximalists or minimalists, whether they prioritize functionality or performance), are broadly applicable in terms of compatibility, provide the most amount of user control, and yet are simple.
I think the way it is meets that criteria. Interestingly that was set by PC Man himself 8 years ago. It hasn’t been changed once. It also does not appear that anyone else has complained since.
Possible, yes. Justifiable? Maybe not. Lubuntu does cater to folks seeking a lightweight solution. While we don’t want to cripple functionality just for performance gains, we’re not going to try to add all of the possible functionality. We’re not going to add support for thumbnails of comics, for example.
Thumbnails do take resources to generate. The fastest library apparently takes roughly half a second of about 80% CPU for a 7 MB file. Consider a folder of hundreds or thousands of such images.
That said, the way it is strikes a balance. It provides thumbnails for most things (including nearly all of our many wallpapers) while not stealing processing power for the largest of images.
And if you don’t like it, it’s easy to change.
If the response here is overwhelmingly in favor of increasing the default, that may help convince us.