So if I understand well, I should resize the image to about the size needed for the inserts?
Yes, but 72 dpi can give too low quality of the graphics. Before editing your document, try to convert one image to 72 dpi and print it on plain paper.
Good quality give the resolution 200-300 dpi and higher. But your document can have much higher resolution on the print (in PDF) when you resize images making them smaller. For instance, the image 100 * 100 pixels with 1 inch per side is 100 dpi. If you resize it to 1/2 inch, it will be 200 dpi.
Note that it is reasonable to convert only raster images such as photos. Vector graphics doesn't take much disk space.
In Preview.app, you can resize images this way:
1. In the menu choose Tools > Adjust Size.
2. Select the measurement units: inches or cm.
3. Deselect Resample Image. Scale Proportionally - selected.
4. Set the desired resolution (I recommend 200-300 dpi).
Now your image has the original quality at specified resolution.
5. Select Resample Image. Scale Proportionally - selected.
6. Set up the image size. Preserving the resolution, Preview.app will reduce the number of pixels and correspondingly the file size.
7. Click OK and save the image using File > Save As.
The blank CD project
We have added several blank projects to the Assistant. But you aren't limited by this. Users can add new elements to the project and remove the existing. Below the toolbar there is the + button that lets you add blank disc labels, booklets, inserts and other elements.
The exported PDF can contain original images from the template if you haven't removed them but placed your graphics over.
If you add a blank design element (a disc label, for instance) you won't have to remove the original images.