No, there is no limit to the number of items that can be contained on the media tab. However, image files can be rather large. If the items are embedded on the Media tab as opposed to being linked, you may hit the maximum database size rather quickly if your organization is using SQL Express. (The database may not exceed 4GB for SQL 2005 Express and 10GB when using SQL 2008 R2 Express.) Therefore, if you are locally hosted and adding many items to the Media tab, we recommend linking to the media object rather than embedding.

If you migrate from a local install to NXT and Blackbaud Hosting Services, we recommend running the Embed Media utility. What is the Media Embed Utility?

All files added to the media tab in the Hosted Environment must be EMBEDDED rather than linked.  For more information, see How to add, edit, or delete attachments (media) in a Constituent record.