Looking at the second image in particular, there appear to be some polygons on the model stretching off into infinity, so it definitely looks like errors happening in the rendering process rather than anything monitor or cable-related. And of course, these appear to be screenshots, meaning they wouldn't be affected by those things anyway.
While the first image might be a photo of the screen, the second actually lists messages to the lower right stating that screenshots are being taken, and at full size is exactly 1440x900 pixels, so it's almost definitely a screenshot.
To add to this, you might try underclocking the card a bit to see if that helps. Most graphics cards tend to be "factory overclocked" to some degree at their default settings, and it's possible that the card may no longer be able to sustain those clocks. So, try reducing the graphics card's memory and/or core clocks a little at a time to see if you can get it working properly again, albeit at somewhat reduced performance.