1. i make a jpg that is 500 x 360 and is the same color as the background color of my page
2. i upload this jpg to my fotola as a private image
3. get the url for the thumbnail because you will need this later. to do this, once you have uploaded your "blank space" image go to http://fotola.com/berylium/serial_me/ and right click on its thumbnail, go to properties and get the address (for example the thumbnail address for andreu's image on this page is: http://fotola.com/fotola/2009/Dec/andreu4b1bde3031b7b-thumb.jpg)
4. click to add an external link on the page where you want the blank image, for the link url, put the url of the page (in this case it would be: http://fotola.com/berylium/serial_me/document-serial_me4b23f5085b778.html) that way if someone clicks on that space it doesn't go anywhere)
5. i leave the optional text blank
6. for the optional image url put the url you got in step 3