If you have Adobe Acrobat (the real deal, not just the reader) you can insert graphics into PDF docs, but it is not intuitive—mainly because Acrobat can only cut and paste graphics within itself, not to/from other programs.
- Click Document menu → Insert Page
- In the Browsewindow, change the file type to your graphics format (GIF, JPG, etc) and select your graphics file.
- The image will be inserted on its own page.
- Click the TouchUp Object tool on the toolbar. Right-click the image and select Cut.
- Go to the page where you want the document and Paste in the image. Drag and drop the image to its correct location.
- Click Document menu → Delete page and delete the (now-empty) page you just inserted.
Resizing the graphics: I haven’t yet figured that out. I am using 5.0 (an old version) so things may be different in the newer versions of Acrobat.