There are two things you can easily do to fine-tune the time length desired for the cache. One option allows you to set the disk cache timeout, and the other one allows you to set the memory cache timeout.
Set the two options below to the desired value before you load the Greta script.
<script> Greta_TTL_Disk = 31536000000 //ms Greta_TTL_Memory = 3600000 // ms </script>
Greta_TTL_Disk allows you to set the time length used for content that is loaded using
live=false (default for all images), and the default value is equal to 365 days.
Greta_TTL_Memory is used for live content, and has a default value of 1 hour.