Nimbostratus
It probably isn't such a good idea to serve up a 1MB image directly from the BIG-IP for a couple of reasons. The first being that TMM can only handle 4MB of data before it will intentionally restart itself. This is to prevent potential swapping to disk as well as interference with other tasks the BIG-IP may be performing. Secondly, for security reasons iRules do not have direct access to the filesystem. If you want to serve up a base64 encoded image from the BIG-IP, the data will either need to be included in the iRule itself or a datagroup. Both of which will reside inside of bigip.conf. If I were in your position, I would spin up an Apache server on a cheap piece of hardware and just use an iRule to send users there.
-George
