Manage attachments

For the first time ever I clicked on the manage attachments in the user control panel. To my astonishment there were pages of them going back a long way. I have now deleted them as they don't seem to serve a particular purpose but it left me wondering would they have slowed my forum loading down? Could I ask . Does the number of downloads against each one really mean its been downloaded or just viewed? some had over a thousand .b

These are attachments you've added to posts. For example if you uploaded a photo to a post it will be listed as an attachment in your UCP. These attachments don't slow the forum down in any way.

I personally wouldn't have deleted them unless absolutely necessary because they will be part of a thread which visitors will look at from time to time.