convert taking system resources, long time

Is it normal for convert to take a long time on a webserver and run up 
the load average?  The input file in this case is not that hefty to 
begin with.

% uptime ; convert 63.2010-04-28-20-06-23.jpg -quality 75 -resize 
300x300 -strip 300.jpg ; uptime
 21:15:23 up 55 min,  3 users,  load average: 0.88, 1.10, 0.66
 21:15:31 up 55 min,  3 users,  load average: 2.89, 1.53, 0.80

% ls -l 63.2010-04-28-20-06-23.jpg
-rw-r--r-- 1 horses horses 49459 Apr 28 20:06 63.2010-04-28-20-06-23.jpg

% ls -l 300.jpg
-rw-r--r-- 1 horses horses 12934 Apr 28 21:15 300.jpg

Or is there a more efficient way to run the command?  If I run the 
command without the -resize option it runs almost instantaneous rather 
than taking 8+ seconds, but of course that doesn't produced the desired 
results.

-Bob