XnView Software

In the browser mode, when roll the mouse wheel - scrolls the thumbnails in spurts,
the default scrolling step = height of the thumbnail. If the thumbnail size by 300 - This scroll becomes uncomfortable ...

Please try to change the setting for scrolling. In menu "Tools > Settings", category "Browser", tab "Browser" uncheck "View scroll the content by thumbnail".

After unchecking "View scroll the content by thumbnail" the default scrolling step even more, = height of the page
And this scroll becomes even more uncomfortable ...