Maybe something like this?

Sub FileSearch()

myDrive = Range("C1")

ChDir myDrive

'set current directory as the one to search
    CurrentDirectory = myDrive

'look in current directory and count the number of jpg files
    With Application.FileSearch
        .LookIn = CurrentDirectory
        .Filename = "*.jpg"
        .SearchSubFolders = False
        
    If .Execute() > 0 Then
        MessageText = "There were " & .FoundFiles.Count & " file(s) found."
        Choice = MsgBox(MessageText, vbOKCancel)
        If Choice = vbCancel Then GoTo leave

        For i = 1 To .FoundFiles.Count
            'call your subroutine here!
            MsgBox .FoundFiles(i)
        Next i
        
    Else
        MsgBox "There were no files found.", vbCritical
    End If
leave:
End Sub