You can physically copy subflows from one Desktop flow to another. You can even save these as text. So Control C on this:

becomes:
Excel.LaunchAndOpen Path: $'''H:\\temp file\\test.xlsx''' Visible: True ReadOnly: False LoadAddInsAndMacros: False Instance=> ExcelInstance
DISABLE Excel.SaveAs Instance: ExcelInstance DocumentFormat: Excel.ExcelFormat.XMLSpreadsheet DocumentPath: $'''H:\\temp file\\test'''
Excel.ActivateWorksheetByName Instance: ExcelInstance Name: $'''Sheet 1'''
SET ExcelFormula TO $'''=COUNTIFS(test2!D:D,D2)'''
Excel.WriteCell Instance: ExcelInstance Value: ExcelFormula Column: $'''M''' Row: 2
And I am pretty sure all the UI data stays captured inside of these. Images will work also if you stay on the same machine. So, if I copy subflow actions that use image based processing over to another flow, I see the images appear in the Image pane.
I have noticed that when UI's are involved, there is a LOT of data, so just prepare for the Paste session to take a while. It freezes my browser if I try to paste it here, but in notepad it works in less than a second, so it just depends on where you are trying to paste it.
Best of luck!