First do a bandwidth test, CNET has a good one to see what kind of speeds you are getting. Do the test at varying intervals over the course of a few days. Also you can use the Windows Task Manager to monitor network performance and see what kind of date rates are being sent and received.
Are 15 images of 60 by 80 pixels to many for page performance, shld a page with 8 such images take 15 min to load
The image load time is awful. 50 images of that size should take just seconds. What format are the images? What is the average file size for the image?
A 60 x 80 pixel image in a jpg format at the best quality possible should load on a 1Mbps contention in about .065 seconds. So about 16 images should load in just a hair over one second.
On the scripting language unless your making a super in depth and complex game that would rival the big boys I would think javascript and PHP could do the job. With all the graphics, sound, ect cached and the only textual data being exchanged between the server and the user, for that to slow down the game would require several thousand lines of text being sent back and forth constantly.
If there is a lot of data exchange your servers hardware configuration and location will effect game speed. You can do a "tracert" in the command line of the computer to see how many jumps are between you and your server and how fast each jump was. You really can't control how fast a router sends data down the line but any slowdowns with in 3 or 4 jumps of the server could be the server owners problem. And jumps with in 3 or 4 of you are your ISP. Both of these you can control. Of course you can't control other peoples ISP so testing on a troubled ISP allows you to see if almost anyone will be able to use your game as many ISP's are plagued by issues at various times.
Also with your servers IP there are some online resources that can tell you who owns the server and/or where it is physically located.
Now maybe the javascript is slowing things down on the users end. There are some good javascript speed testing scripts out there. Find one and run it. They each usually loop through the same line of code many many times and then report in seconds how long it took. So all you need to do is figure out what your most complex operations is and how many lines of code are being handled and them compare and see if javascript is the slow down point. I would think it would take 10s of thousands of lines of javascript in a process before you saw any problem.