Loop with selection.delete and InStr is ending early

Seem like deleting the first cell C2 on range "C2:C18" cause the C3 to skip
Change C2 to C1 fix it

Sub CleanUp_TMS()

Dim lastrow As Long
Dim cel As Range

'this will move region to column b and leave a 2nd location if there is one in column a
lastrow = Range("A" & rows.Count).End(xlUp).Row

Debug.Print Range("a2:a" & lastrow).Address
For Each cel In Range("a2:a" & lastrow)
    Debug.Print cel.Address, cel.Value
    If InStr(cel.Value, ":") > 0 Then
        cel.Insert Shift:=xlToRight
    End If
Next cel
 
'remove photo lines out of Column C
Debug.Print Range("c2:c" & lastrow).Address
For Each cel In Range("C1:C" & lastrow)
    Debug.Print cel.Address, cel.Value
    If InStr(cel.Value, "photo") > 0 Then
        cel.Delete Shift:=xlToLeft
    End If
Next cel

End Sub

or try

PHP Code: 

Sub cUp()

Dim a, i&
a = [a1].CurrentRegion.Value
For i = 1 To UBound(a)
    If InStr(a(i, 1), ":") Then
        If InStr(a(i, 2), "photo") = 0 Then
            a(i, 4) = a(i, 3)
            a(i, 3) = a(i, 2)
        End If
        a(i, 2) = a(i, 1)
        a(i, 1) = Empty
    End If
Next
[a1].CurrentRegion.Value = a
End Sub