I checked my page using PageSpeed Insights and I found out that images from jo k2 slideshow don't have espiration date Below is the list. How to set it up?
/modules/mod_jo_k2_slideshow/images/load-indicator.gif (expiration not specified)
/modules/mod_jo_k2_slideshow/thumb_article/thumb_6760.gif (expiration not specified)
/modules/mod_jo_k2_slideshow/thumb_article/thumb_6823.gif (expiration not specified)
/modules/mod_jo_k2_slideshow/thumb_article/thumb_6828.gif (expiration not specified)
/modules/mod_jo_k2_slideshow/thumb_article/thumb_6855.gif (expiration not specified)
/modules/mod_jo_k2_slideshow/thumb_article/thumb_6859.gif (expiration not specified)
/modules/mod_jo_k2_slideshow/thumb_article/thumb_6861.gif (expiration not specified)
thanks in advance,
Kalixo