Good Morning,
Yes, to make an envelope, you upload the desired picture in paint.
Then you type the addresses on/ above/ next to/ the picture.
Then you rotate the picture 90 degrees
then you print out the page on lightweight card stock.
then fold the page longwise and you have the addressed envelope. Trim to suit.
then glue sides and top, insert letter, then fold to glue envelope shut.
 stamp and mail.
SAVE; and the next time rotate picture back left, change address,
rotate right  and repeat!
Enjoy, Lewis