I take a lot of screen shots. Daily. Sometimes dozens a day, depending on what I’m writing about.
I use SnapzPro for this work. I save the image to the desktop and later move it into a folder.
I can be sailing along, have 12 or 15 screen shots, and suddenly they stop appearing on the desktop. Turns out this is a known OS X bug. The file is there, you just can’t see it.
I’ve used spotlight to search for it and open it in preview. Then I do save as and replace it. That pops it into place on the desktop. It also works to do the same shot again and click Replace when the Mac tells you the item is already on the desktop. Again, this pops up the image icon on the desktop. You can also select Go > Desktop when in the Finder or select Desktop in a Finder window. When the Desktop folder opens, click the item to make it appear.
No matter which method you use, it’s a pain and several extra clicks to get what you need to show up on the desktop.