[Christian Rivera]

Hi! Since this afternoon some thumbnails are not loading. I’m adding some files to an existing folder but those thumbnails are not showing. They have the same structure as the old folders with the thumbnails working as expected. I tried reinstalling PM, old version, newest version, same version, cleared cache, updated cache, restores an old database but nothing works. In the link you can find an screenshot of the problem

https://www.dropbox.com/scl/fi/g7wjuslbul4kjce8megk1/thumbnails-not-working.JPG?rlkey=8tva1qa63gzcltxbxgt3pteiv&dl=0

Plugin version: 3.43.18
3ds Max version: 2026
Renderer: Corona

[Oleksandr Kramer]

Before I can help narrow this down, I have a couple of quick questions:

1. Is it always the same specific files that won’t show thumbnails, or does it change — sometimes different files in the same folders fail to load?

2. Did anything happen just before the issue started — for example, did Windows or your antivirus update, did you move or rename any folders, or did a drive go offline?

[Christian Rivera]

Hi!

 

1. It’s always the same files, old files works perfectly, any new files added don’t show thumbnails
2. Nothing has been updated, no renaming folders or something similar.

[Oleksandr Kramer]

Please send a few of these files to me.

It looks like they are stored in incorrect format.

[Christian Rivera]

Here you have a couple:

https://www.dropbox.com/scl/fo/b2a2j8zcknpojpc7gl9sh/AG17JQN3YG4tzXZUUDOWw0Q?rlkey=rb2frw5mcxzejmrmkqnfwx271&dl=0

[Oleksandr Kramer]

It looks like the new thumbnail files are actually in WebP format but have been saved with a .jpg extension — Project Manager reads the actual file content, so it can’t load them as images.

The fix is straightforward: please re-save or convert those thumbnail files to proper JPG format and replace the existing ones. Once done, the thumbnails should load correctly.

If you’re not sure which files are affected, you can identify them by checking the file header — a real JPG starts with FF D8 FF, while a WebP file starts with RIFF. Any image converter will let you re-export them correctly as JPG.

I’ll also look into adding a fallback for mismatched image formats in a future update — as long as it doesn’t negatively impact thumbnail loading performance.

Kind regards

[Resolved]

[Christian Rivera]

Thanks for the response!

It was the reason. Maybe there was a change in 3dsky’s thumbnails. I always downloaded them directly from the site and they worked but suddenly they this problem appeared.

I just created a script for batch checking header and converting that works like a charm. Now it’s all fixed!

Thanks!

[Resolved]