[IDL] How to save IDL plots

1. How to save an IDL plot as a jpeg file

After you made your plot in IDL you can type the following:
IDL> im=tvrd() ; im is the matrix for the image
IDL>write_jpeg,'filename.jpeg',im ; a file named filename.jpeg is stored in the current IDL working directory

2. How to make a PostScript plot

IDL> set_plot,'ps'
IDL> device,filename='name.ps'
IDL> {set of instructions to make desired plot}
IDL> device, /close
IDL> set_plot,'x'