The short answer is no, and it would be better if you ran the process from Excel or Word as Outlook doesn't have the filedialog selector, but it can be done from Outlook VBA e.g. as follows. Run the macro and select the file to attach.
Code:
Option Explicit
Sub Send_As_Attachment()
'Graham Mayor - https://www.gmayor.com - Last updated - 09 Jul 2019
Dim olItem As MailItem
Dim olInsp As Inspector
Dim wdDoc As Object
Dim oRng As Object
'Change the values below as appropriate
Const strSubject As String = "This is the message subject"
Const strRecipient As String = "someone@somewhere.com"
Const strMessage As String = "This is the message body text" & vbCr & vbCr & _
"This is another paragraph of message body"
Set olItem = CreateItem(0)
With olItem
.BodyFormat = 2
.To = strRecipient
.Subject = strSubject
.Attachments.Add BrowseForFile
.Display
Set olInsp = olItem.GetInspector
Set wdDoc = olInsp.WordEditor
Set oRng = wdDoc.Range
oRng.collapse 1
oRng.Text = strMessage
'.Send
End With
lbl_Exit:
Set olItem = Nothing
Set olInsp = Nothing
Set wdDoc = Nothing
Set oRng = Nothing
Exit Sub
End Sub
Function BrowseForFile(Optional sName As String) As String
Dim exApp As Object
Dim strPath As String: strPath = ""
Dim fDialog As FileDialog
Dim bStarted As Boolean
On Error Resume Next
Set exApp = GetObject(, "Excel.Application")
On Error GoTo 0
If exApp Is Nothing Then
Set exApp = CreateObject("Excel.Application")
bStarted = True
End If
Set fDialog = exApp.FileDialog(msoFileDialogFilePicker)
With fDialog
.Title = "Select attachment"
.AllowMultiSelect = False
.InitialView = msoFileDialogViewList
If .Show <> -1 Then GoTo err_Handler:
BrowseForFile = fDialog.SelectedItems.Item(1)
End With
lbl_Exit:
If bStarted = True Then exApp.Quit 'Optional
Set exApp = Nothing
Exit Function
err_Handler:
BrowseForFile = vbNullString
Resume lbl_Exit
End Function