[squid-users] refresh_pattern and forcing "gifs" to be cached

Hello.
I've been tracking the usage logs of my squid cache, and I've notisted
frequently behaviour like this (I've cutted some fields):

x614.374 1043 <IP> TCP_MISS/200 379 GET http:<URL>/piexel_preto.gif
x614.426 1044 <IP> TCP_MISS/200 390 GET http:<URL>/piexel_01_09.gif
x614.939 563 <IP> TCP_MISS/200 390 GET http:<URL>/piexel_01_17.gif
x615.181 754 <IP> TCP_MISS/200 389 GET http:<URL>/piexel_trans.gif
x618.935 432 <IP> TCP_MISS/200 389 GET http:<URL>/piexel_09_01.gif
x660.841 1198 <IP> TCP_MISS/200 395 GET http:<URL>/piexel_cinza_claro.gif
x721.748 1195 <IP> TCP_MISS/304 261 GET http:<URL>/piexel_preto.gif
x723.345 1596 <IP> TCP_MISS/304 262 GET http:<URL>/piexel_01_09.gif
x723.769 1457 <IP> TCP_MISS/304 261 GET http:<URL>/piexel_01_17.gif
x728.731 5385 <IP> TCP_MISS/304 262 GET http:<URL>/piexel_trans.gif
x730.503 1771 <IP> TCP_MISS/304 261 GET http:<URL>/piexel_09_01.gif
x735.851 10471 <IP> TCP_MISS/200 381 GET http:<URL>/piexel_azul.gif
x774.326 217 <IP> TCP_MISS/304 262 GET http:<URL>/piexel_01_09.gif
x774.520 192 <IP> TCP_MISS/304 261 GET http:<URL>/piexel_01_17.gif
x776.385 1865 <IP> TCP_MISS/304 262 GET http:<URL>/piexel_trans.gif

As you can see, I've got misses over and over again altough each image
is asked at least two times in a very short space of time.

If i'm not mistaken there would be no problem on getting these cached,
so I was willing to try "forcing" the caching of gifs and jpegs.

My touhgt was of adding a rule to refresh_pattern to get gifs and jpegs. I
would like to know if changing "percent" to a greater value would help in
any way.
If not, I think I'll try to add a rule stating a minimal freshness.
(as the manual says "'Min' is the time (in minutes) an object without an
explicit expiry time should be considered fresh")

Can someone share some toughts with me if it would be feasible and if,
restricted to some contents, this can be used without "hurting" my users?

One other thing: As I see it, this will work if the sites I've seen do NOT
set a expiry time. How can I see, from some squid log, that these sites
set or not the expiry time?

Thank you
Joao Clemente

-- 
		        	Joao Pedro Clemente
        			jpcl @ rnl.ist.utl.pt
					(when not working out)
					(when not sleeping)
					(when not surfing)
					(when not ... ;)