In the app, when I review a transaction, is it possible to add a picture

Hi jasper-tidalgold,

Welcome to Community!  QuickBooks Online simplifies the way you can add attachments to transactions, customers and suppliers.  Your success is our number one priority and I'd be glad to assist!

It's important to understand what file types are compatible with QuickBooks Online, to protect the security of your account.  Here's a helpful guide for adding attachments.  In addition, you can capture and upload receipts and bills from your mobile device.  This is a great time saver!

I also recommend taking a look at the available tutorials for the QuickBooks Online mobile app.

If you have any other questions, feel free to reach back out.  We're here for you!