Avoid dealing with the BLOB on every query
Shamelessly lifted from this email from TobiasLuetke
Now, this will create three Image objects, right? So, if each image is 500KB, that’s at least a 1.5MB database transfer (right?). I really only need each image id.
I store my images in the database too but have a File model which has a belongs_to :binary
The binaries tables has the actual data, the File table has just the information about it (eg: format, mime, imagesize, filename etc )
This lets you use File as normal active record object and only receive the blob when needed over the binary relation.
Also see Caching images in Rails for a clever way to avoid performance hits when using a database to store images (and files).