Select by extension

[stevehero]

Being able to select by extension would be a nice feature.

[michel038]

Is this method a way to achieve what you want ?
View > Sort by > show headers
Click on "Type" header ... so files ar sorted by type

Other settings :
View > View as > Details
Now you can move or add or remove columns, and if necessary enable "Extension" column, and bring it to the left ...
and go back to : View > View as > Thumbnails + labels

[helmut]

In addition to Michel's good suggestions above: You can use the quick filter in the toolbar. In the quick filter you enter the desired extension (e.g. ".png") this will display all files that match this pattern, only. Then press Ctrl + A for selecting all files.

[cday]

In addition to Michel's good suggestions above: You can use the quick filter in the toolbar. In the quick filter you enter the desired extension (e.g. ".png") this will display all files that match this pattern, only. Then press Ctrl + A for selecting all files.

I don't see that option on the toolbar of my installation of XnView MP 1.3 with default toolbar settings, but maybe I'm missing it as I rarely use the browser functions.

Either way, the following menu option looks like a useful alternative solution: View > Sort by > Extension.