Sitecore and BLOB

Sitecore stores images as image type, which it has its own advantages which is listed in following.

1-BLOB data is backed up with the database. Having a single storage system can ease administration.
2-Databases efficiently handle large numbers of small objects

In other hand it has its own disadvantages comparing saving images as File system on hosting on web server or CDN

1-By adding more images to database,  the database size gets a lot larger and retrieving an image from a database incurs significant overhead compared to using the file system
2-You can't do incremental backups with blobs in a database, you can with files on a file-system
3-It makes the database size grow so fast .Disk storage on database servers is typically more expensive than storage on disks used in Web server farms.
4-Big size database takes more administration time to  get backup or restore

based on the research has done by Microsoft ( This study shows that when comparing the NTFS file system and SQL Server 2005 database system on a create, {read, replace}* delete workload, BLOBs smaller than 256KB are more efficiently handled by SQL Server, while NTFS is more efficient BLOBS larger than 1MB.
It’s hard to ask your sitecore content users to upload images smaller than 256KB for better efficiency.

Microsoft introduced a new way of storing blob data in sql server 2008, which combines the benefit of saving images in database and efficiency of using NTFS (

Some experts are saying a valid point that Sitecore caches all the images in the media library, then having images in DB or on file system doesn't affect the web application performance. But, the growing database size is still an issue.

I suggest to change sitecore default setting  and start saving your images as file system and take advantage of it for your next sitecore build.

Sitecore allows you to do it with two simple line of settings .
<setting name="Media.UploadAsFiles" value="true">
<setting name="Media.FileFolder" value="/App_Data/MediaFiles">