This is an example of how to determine which controls in an array are loaded. This particular snippet works for a picturebox array called picture1.

VB Code:
  1. Dim pic As PictureBox
  2. Dim strLoaded As String
  3.  
  4. Private Sub Form_Load()
  5.     For Each pic In Picture1
  6.         a = pic.Index
  7.         strLoaded = strLoaded & a & ","
  8.     Next
  9.     strLoaded = Left(strLoaded, Len(strLoaded) - 1)
  10.    
  11.     'strLoaded returns the indexes of each loaded control in the array delimited with commas.
  12.     MsgBox strLoaded
  13. End Sub