Exchange Online has been updated to introduce a new feature in Outlook on the Web (aka Outlook Web Access, aka OWA).

When accessing your mailbox using OWA, you will now see a Files view, available in the module switcher at the bottom (which redirect you to https://outlook.office.com/files/)

When you switch to the Files view you will have access to all attachments you have sent or received; you will notice it can separate files (like Office documents) from pictures