inserting an image created by a shell script...

[tdjb]

I think this probably has an easy solution but I've yet to find it.
I've created a bash script that reads some SNMP data from an IP (user defined) and creates a graph (in .png format) using gnuplot. This image is dropped into a set directory on the server.
Now I've created a php webpage/form that a user can go to and input the IP, press submit and the file is created but they manually have to type in the address of the image to see it. What I'd like to do is have that file that was created be inserted into the page on the fly.
Is there a quick and dirty way to make this happen?
I assume one of the problems is the bash script doesn't echo out anything like the filename so PHP doesn't know what to insert...

Thanks in advance