Public Function Busqueda(folder As String, ext As String) As String
On Error Resume Next
Dim cr As String, cx As String: str1 = folder
cr = Dir$(folder + "*." + ext)
While cr <> ""
cx = cx & cr & "|"
cr = Dir$
Wend
End Function
Private Sub Command1_Click()
buf = Split(Busqueda("C:\carpeta_con_imagenes\", "jpg"), "|")
MsgBox
Picture1.Picture = LoadImage(str1 & buf(Int((Rnd * UBound(buf)))))
End Sub