Specifies attributes for items in Thumbnail GUI window.

Values:

IG_GUI_THUMBNAIL_ICON_NPAGES	Attribute specified is a number of pages in the image file.
IG_GUI_THUMBNAIL_ICON_PAGENUMBER	Attribute specified is a page number.
IG_GUI_THUMBNAIL_ICON_ISMULTIPAGE	Attribute specified is a flag indicating whether the image file is multi-page (value is TRUE) or not (value is FALSE).
IG_GUI_THUMBNAIL_ICON_FILENAME	Attribute specified is a file name.
IG_GUI_THUMBNAIL_ICON_TITLE	Attribute specified is an icon title.
IG_GUI_THUMBNAIL_ICON_DATA	Attribute specified is a data associated with icon.
IG_GUI_THUMBNAIL_ICON_DIB	Attribute specified is a HIGDIBINFO DIB information.

Remarks:

See IG_GUI_thumbnail_data_get description for more info.