How to reduce the size (in MB) of pictures inserted in a PDF?

I'm writing a Master thesis when I need to include severa开发者_开发技巧l photographs, but I've got a problem with the size of the generated PDF: 18MB, which is more or less the cumulated size of all the picture included.

How can I tell Latex not to keep the original picture and reduce it, but to shrink the picture before including it in the PDF?

I use \includegraphics[height=6cm]{img/cinema.jpg} to include my figures.

Thanks

---

You need to reduce the size of your pictures yourself before you include them (with software of your choice). That's the simple solution.

I think the rationale for including in full is that PDF is a vectorial page description language, and you might want to render a page at an arbitrary resolution later.

---

You can use primoPDF to downsize all pictures at once, after you created the pdf in Latex.

---

There is a package called "degrade" that does this. I have not tried it, and it is not included in TeXLive, so you will need to install it manually.

Also, PDFLaTeX should have some compression arguments.