I am retrieving the contents of the display panel of a printer in the form of a GIF image.
(More information here http://www.mibdepot.com/cgi-bin/getmib3.cgi?i=1&n=LJ4200-MIB&r=hp&f=lj4200.mib&v=v1&t=sca&o=control-panel-display-graphical-contents
I am able to retrieve the OID and using GetNext, obtain the remaining chunks of the image in this tree. I used StreamWriter to directly write the values to a file (each SNMP octet stream is directly written to the filestream) The first 480 bytes came in the first GET and then an additional 5 bytes in the second GET
But for some reason the image isn't valid. I looked at the output in a hex editor and there are 4 bytes _before_ the "GIF89a" header. I tried removing the first 4 bytes of the file but no luck.
The invalid GIF can be found here: http://www.ls1powered.net/test1.gif
<< Try saving it locally and looking at it in a hex editor.
Does anyone know what's wrong with this GIF?
If you figure out what's wrong with the file, I need to know what portion of the file was changed to make it valid.