When you change anything in a card it is automatically shown as an activity.

There isn't a way to specifically mention an attachment, but you can mention a member member anywhere by using @MemberName. So you can just say something like:

@John Doe, check attachment WireFrame.Jpg

Or

@John Doe, check my last activity (being that it was the attachment)

When you change anything in a card it is automatically shown as an activity.

There isn't a way to specifically mention an attachment, but you can mention a member anywhere by using @MemberName. So you can just say something like:

@John Doe, check attachment WireFrame.Jpg

Or

@John Doe, check my last activity (being that it was the attachment)