I have found the easiest way is to use the Content Editor Webpart (CEW) to add graphics to pages.
- On the page you want to add your graphic. Go to Site Actions> Edit Page.
- Add a Content Editor Webpart in the Add a Web Part section of the page where you want to add the graphic. If you want to add text with your graphic you can add text with it too.
- In the ribbon, look for the orange Editing Tools tabs, go to Insert> Picture >From Computer. Browse for your picture from your harddrive. Remember to not get too large of an image or you may need to resize it to properly fit what you are trying to achieve.
- You'll notice that is also say's Upload to: - this is where you want to save your picture on the SharePoint server, either choose SiteImages if you have a SiteImages library or SiteAssets. You don't want to put it in any of your document libraries and mix it with your documents. You may need to create a new SiteImages picture library if you don't have one.
- Once you hit OK, it saves your picture to the SharePoint server (your library) and to your page.
From there you can go to the Format Text and center the paragraph and center the image or you can go to the Picture Tools and choose how to position the image, put a border on it or not, etc.