Use of FileDialog object of Application required for this purpose

This object has a property InitialView which can be set to the
following constants

msoFileDialogViewList
msoFileDialogViewThumbnail
msoFileDialogViewDetails

One snippet for reference

With Application.FileDialog(msoFileDialogOpen)
.InitialView = msoFileDialogViewThumbnail
If .Show Then .Execute
End With