Thumbnails 4mb is the default in file dialog.

[hemkr]

My picture is 15mb, so it cannot be displayed.
Could you let me set the file size?

[hemkr]

Thumbnail settings work well with pcmanfm-qt.
But if you open the file on Chrome, it's not more than 4mb.

[tsujan]

pcmanfm-qt's settings aren't related to LXQt file dialog. The latter doesn't have a setting for the maximum thumbnail size yet.

[tsujan]

The basic implementation is very simple: just a new sub-menu with a spin-box should be added. But there is an important problem:

If LXQt file dialog is opened by an app that depends on libfm-qt (like pcmanfm-qt and lximage-qt), any change in its maximum file size will affect the same setting in that app. For example, as soon as lximage-qt opens a file dialog, the maximum file size of that dialog will be set in lximage-qt too. The reason is that libfm-qt is shared by lximage-qt and its file dialog.

There may be three solutions, but none of them seems good to me:

1. The file dialog may be able to check libfm-qt's reference count and not show the new sub-menu when it's more than one (i.e., when there is a libfm-qt-based parent app). I think this will need a deep change in the code, which is ugly. Moreover, there is no guarantee that a libfm-qt-based app should have an option for this property.
2. We can make the code tell us about any change in the maximum file size. Then we could add the sub-menu only if there has been no change (made by the parent app). The problem with this approach is that it becomes quite confusing with an app that is not based on libfm-qt and can open two or more file dialogs simultaneously.
3. libfm-qt-based apps could share their maximum file size with LXQt file dialog when they're running under LXQt. This solution is bad because it's backward incompatible, if not confusing, In addition, we can't tell developers, "Do not use a separate setting for maximum thumbnail file size!".

[tsujan]

@hemkr
Until an acceptable solution is found for the above-mentioned problem, you could first open the folder inside pcmanfm-qt for thumbnails to be created. After that, LXQt file dialog will show them.

[hemkr]

thank you ^^

[tsujan]

I'm out of ideas. Will add the option if someone finds a solution for the above-mentioned problem. If anyone has a suggestion, please forget about coding and describe it in English!

[hemkr]

How about making thumbnails basic memory 15mb?
Pictures taken with digital cameras do not exceed 15mb.

[tsujan]

How about making thumbnails basic memory 15mb?

The default (4 MiB) is good. We shouldn't change it just because of this case.