Yes. You can attach a photo to a transaction and/or add a note about what the transaction was for or who it was with.
From the transaction tab, tap the i icon located above the amount to get to the detailed view. From here you can add a note or attach a receipt. If you are in the Search tab, tap on the transaction to view the details. At the bottom of the screen you can either add a note, or attach a receipt by either taking a photo or accessing a photo from within your phones library.
Note that IRS only requires receipts for expenses >$75.
For more information see IRS web site Adequate Records