LARTC - May 2004 - Browsing speed becomes slow

Hi all,
 
I hv installed Linux 7.2 for proxy. 
PC config: P-II, 128MB RAM, 20 GB HDD.
MY LAN is mixed with 10 & 100 MBPS switches.
 
I hv a band width of 64K Broad Band. 
25 Users are browsing thro'' this proxy. If all the users start
browsing,
Browser displays half the page & stops over there. 
Users visit the image sites like fpg.com, corbis.com etc. 
The Squid is not so effective. But defenitely good when 10 users use
this.
 
How can i solve this prblm ? 
 
Regs,
S.Ganesh