What are info icons?
Info icons can be shown in the XnView browser for each thumbnail.
In the following screenshot of the XnView browser, you can see thumbnails with info icons:

From left to right the info icons mean:
Arrow: The file is a shortcut to an image file.
[EXIF]: Image has EXIF information (Info written by digital camera)
[IPTC]: Image has IPTC information (Info typically entered by author of image)
Rotate symbol: The image is automatically rotated according to the EXIF orientation info.
Small square: For displaying the thumbnail of this image, the embedded JPG thumbnail is used.
Can I hide these info icons?
If you do not need the info icons and their extra info, you can hide the info icons. Open the options dialog (Tools > Options), category "Browser > Thumbnail", and deactivate the checkbox "Show info icons (EXIF/IPTC/Shortcut)".
Note:
Part of the above info is taken from thread "Info Icons on Thumbnails"