Folder thumbnail no longer shows the first image inside a ZIP archive (Regression in 1.9.0+)

[keroroqq]

Applies to:

Worked fine in: XnView MP v1.8.8 (x64)

Broken since: XnView MP v1.9.0 (x64) up to v1.11.5 (x64)

OS: Windows 10 / 11 (x64)

Description:
In version 1.8.8, if a folder contains no loose image files but contains ZIP archives with images inside, the folder thumbnail automatically previews the 1st image from the 1st ZIP archive.

Since version 1.9.0 (including the latest 1.11.5), this behavior is broken. Folder thumbnails can only show direct image files, and images inside ZIP archives are completely ignored for folder preview.

Folder Structure Example:
Plaintext

Folder/
├─ 001.zip
│ └─ 001.jpg <-- Should be displayed as folder thumbnail when no loose images exist
└─ 002.zip
└─ 001.jpg

Steps to Reproduce:

Create a folder containing only ZIP archives (each ZIP containing image files) and no direct image files.

Open XnView MP and browse to the parent directory.

Observe the generated folder thumbnail.

Expected Result:
The folder thumbnail shows the 1st image from 001.zip (Works in v1.8..

Actual Result:
The folder thumbnail fails to preview the image inside the ZIP archive and displays a generic folder icon instead (Broken in v1.9.0 ~ v1.11.5).

Additional Info:
I have attached my xnview.ini file from v1.8.8 (where this functionality works as expected) for your reference.

xnview.zip

Below is a screenshot showing the folder thumbnail preview working normally.

snap004.jpg

snap005.jpg

snap006.jpg

[xnview]

i'm not able to reproduce on a clean windows 11, XnView 1.8.8 doesnt display a picture for .zip
you have the same on windows 10 or 11?

[keroroqq]

I use windows 10.

After further testing, I found specific conditions required to reproduce/trigger the image preview inside ZIP archives:

ZIP Compression Level Requirement:
The folder thumbnail only works if the ZIP archive was created using the "Store" (No Compression) method. If the ZIP archive is compressed (e.g., standard compression), the image preview inside will fail to render.

Please refer to Image 1: The left side shows a ZIP file created with the "Store" method (thumbnail displays correctly), while the right side shows a compressed ZIP file (thumbnail fails to render).

001.jpg

002.jpg

003.jpg

xnview.ini Configuration:
Please ensure that the parameter in xnview.ini is set to:
thumbnailFilter=65535

Other values for thumbnailFilter may prevent ZIP thumbnails from showing up at all.

i-006_壓縮最佳.zip

i-004_僅儲存.zip

[keroroqq]

To exclude any interference from local system settings or thumbnail caches, I tested this issue inside a fresh Windows 10 Sandbox:

Clean Environment Test Results:
Using a clean installation of XnView MP v1.8.7 (tested one version prior to 1.8. with default settings, the folder thumbnail displays the images inside the ZIP archive normally. This confirms that this functionality worked out-of-the-box in the 1.8.x release branch.


(Note: It seems the official download links for older versions currently redirect to the latest version.)

005.jpg

005a.jpg

006.jpg

[xnview]

Thanks to your detailed description I can reproduce the problem.

[xnview]

This problem is supposed to be fixed in XnView MP 1.11.7. Please check and confirm the bug fix here.

[keroroqq]

Thank you for releasing v1.11.7.

Unfortunately, this issue does not seem to be resolved in this version yet. Folder thumbnails still fail to display the images inside the underlying ZIP archives.

All tests below were conducted in a completely fresh state (clean environment with default settings):

v1.11.7 Screenshots:

003.jpg

004.jpg

v1.8.8 Screenshots (Working reference):

001.jpg

002.jpg

Thank you for looking into this issue. Please let me know if you need any further information or help with testing!

[xnview]

Please try to go to 'Settings>Custom filter', Press OK, select the zip file and 'View>Rebuild thumbnails'

[keroroqq]

After testing, the thumbnails still fail to display. Please refer to the recorded video attached/below.

bandicam 2026-09-25 11-21-14-062.mp4

[xnview]

if you change to thumbnailFilter=1253 in your xnview.ini?

[keroroqq]

I have set thumbnailFilter=1253, but the thumbnails still fail to display.

snap050.jpg

[xnview]

Please remove the vTab line in [Preview] of xnview.ini

[keroroqq]

I have performed further tests:

I deleted vTab under the [Preview] section in xnview.ini, but folder thumbnails still do not show up after restarting XnView MP.

Additionally, upon restarting, vTab=65405 is automatically regenerated under [Preview]. I manually modified this value to vTab=65535 and saved it, but folder thumbnails are still not displaying.

[xnview]

I have performed further tests:

I deleted vTab under the [Preview] section in xnview.ini, but folder thumbnails still do not show up after restarting XnView MP.

Additionally, upon restarting, vTab=65405 is automatically regenerated under [Preview]. I manually modified this value to vTab=65535 and saved it, but folder thumbnails are still not displaying.

please send your xnview.ini

[keroroqq]

ok here is .

xnview.zip