Just a quick question.
Is there a way to setup the thumbnail lister mode, to display Image thumbnails before it displays video thumbnails as the folder preview.
Currently it displays Video previews before image previews even if the images are alphabetically sorted before the videos.
I am wonder if there is an option to change this behavior to have Dopus prefer Images over Videos for the thumbnail lister.
Thanks.
There's no way to give one type of file priority over another.
Opus should normally work from the top-left to the bottom-right. (There are exceptions, like it will only generate one video thumbnail at a time because of problems with codecs that aren't thread-safe. Also, if you scroll around the thumbnails then Opus will move the ones currently in view to the top of the queue.)
Yea I do not understand it at on how it know what to choose.
Windows explorer takes the most recently created file or image.
Dopus seems to randomly choose to display either videos or images.
Ex: There are some folders, with videos of the same exact format, and the images were added after, yet it displays some folders as the videos and other half as images.
Videos starting with any kind of blackscreen are highly unhelpful and that is why I prefer images which I can add, but there appears to be no way of customizing this behavior =[
Oh, do you mean for the actual folder thumbnails (as in when you view the parent of the folder in thumbnails mode)?
I think Opus picks the first four files from the directory listing which can be turned into thumbnails. That's usually the most recent four files but not always.
Yes that is what I mean.
(I would have provided a visual, but umm, well nvm haha)
Anyway, yes that is usually the case: 4 most recent (or it might be created data). But to ensure that the folder must be renamed and then refreshed using F5.
But even then there are times when it doesn't work.
I am not sure if there is a way to change this behavior to maybe "Exclude video thumbnails when there are images in the folder instead" or something similar.
Can't be changed at the moment, except for the Text-File Thumbnails plugin which has an option to exclude its thumbnails from Folder thumbnails.
Hey I think I have a work around for now. By doing trial and error, it appears if there are more images than videos, Dopus will display 4 of the images, instead of the videos =]
But in the future, options to configure this behavior would be nice =]
I should probably clarify:
The work around only works about 40% of the time. The other 60% it constantly seems to want to prefer videos to images in thumbnail mode.
Hopefully in the future we can at least get an option that tells Dopus to cache the image thumbnails to videos ones. And if there are video ones that are already cached, check to ensure that no images still exist in the directory. If so then show them instead.
I think now Opus picks the four files with the most recent Modified timestamps. It doesn't decide "I'll do all videos" or "I'll do all images," it's trying to show you the most recent files.
I have noticed that, but doing tests, it seems that has sometimes been the case, and other times not.
I feel like it also depends on when the user views the folder in opus (if user view folder when it already has images in then, then usually they stay locked in the cache, but if it has videos, I feel like it is preferring them.
Been looking for the exact algorithm required to make opus display what I want, but I feel like I am playing a game of Russian roulette.
Once the thumbnails get locked in the cache, there is no way to remove, change, modify, or delete them for 1 folder.
Only way for it to "rebuild" its DB is to clear it all and then wait hours for the threads to eat up CPU time processing the thumbnails for all folders.
The exception to thumbnails getting 'locked' into cache, is when dopus decided to change cached image thumbnails to video thumbnails. Then it seems like it will never change at all.
Frustrating indeed.
Should also clarify:
"Then it seems like it will never change at all. "
EXCEPT when renaming the folder... but you can never use the previous folder name again, until you rebuild the entire cache, or it will revert back.
I tried searching for folder names & paths manually in the cache directory, but from the large amount of files, and various searching patterns, it is difficult to find any for the specific folder you are looking for.
Tried changing some of the hex bytes within the file to different folder names, but seemed to have no effect. 
You can use the Go REFRESHTHUMBS command to clear the cache for the current folder.
I am not sure where you are talking about exactly.
I looked under the Go menu, but there is nothing in there (Atleast for the version I currently have isntalled 9.1.1.5)
Also tried typing in REFRESHTHUMBS in the address bar, but with no effect.
I looked in the changelog to see if there is anything about this, but a search for "REFRESHTHUMBS" turned up nothing.
If this is a new feature, what version was it implemented in?
You have to make a button/hotkey/menu-item which runs that command. It's an old feature; older than 9.1.1.5.
Wow, I would have never found that, unless it was just by mistake, lol.
Ended up doing:
This will refresh the thumbnails displayed for all sub folders.
Indeed that is EXACTLY what I was looking for, because you no longer have to rebuild the whole building to just modify one room.
That should have been included on the toolbar 
In any case, I am able to change the Date Modified on the 4 files to be preferred, and then execute that command on its parent folder.
I guess the issues before would be how I would put images in folders with videos, and many times the videos would be preferred because they take minutes to download, thus causing them to always have a more current Date Modified attribute.
The odd behavior was that, the images were preferred and 'locked in' if the video file was still downloading -- Probably due to the fact that the video file was still downloading, and thus, Dopus couldn't find a valid thumbnail in the file, and processed the images instead.
So basically, if I browsed to the folder’s parent, before the videos were done, the thumbnails would be cached and locked in instead.
Other wise, if I waited until the videos were done before browsing to the folder’s parent, then the videos would be cached.
Wow, finally solved!
In the future, it would still be nice to be able to fine tune Dopus' preference, such as creating a filter for how it determines which thumbnails to display.
Ex: Date Modified VS Date Created, Specific Img/Video files types, or Prefer Image filetypes to Video file types (or vise versa)
Just something to consider.
Some notes:
It appears Dopus chooses the thumbnails to display based on the files with the most recent Date Modified
It does not work for Date Created nor Date Accessed, only the most recent Date Modified.
The GO REFRESHTHUMBS command only works for subfolders, but the current folder (To refresh the current folder, do a refresh on its parent folder)
To change the thumbnails for a cached folder without having to rename it:
Use an application that allows you to change the file properties for files, and do so for the 4 images/videos that you want to be the thumbnails for that folder. -- Ensure the Date Modified surpasses that of any other files in there.
Go up one folder to its parent folder, and perform the GO REFRESHTHUMBS command (such as through a hotkey)