No, we’re not talking about the graphic result of a violent action. Bleeding is a term in printing where an image overlaps the edge of the paper so there is no unprinted margin.
Often it is easy to simply paste an image onto your PowerPoint or Keynote slide with some text above or below it.
A far more effective way to present this would be to bleed the image beyond the edge of the slide. Below, notice that the image is much larger than the slide, actually spilling off of the slide on the top, right and bottom. With the image now completely filling the slide, the text is on top of the image in a contrasting color.
You may not always be able to simply enlarge a small image to fill the slide – it may become to pixelated and blurry. You will have to use an image with a suitably high resolution. Or another trick might be to stretch the image.
There are a couple of other concepts worth noting. The subject should not necessarily be centered in the image. Imagine the image divided into thirds, left to right and top to bottom. The rule of thirds positions the subject in the left or right third, and/or in the top or bottom third. This is an important concept even without the text, but here it provides us room for our text, and notice that the text is also in the top third of the image.
Another concept is the color of the text. It would have been easy just to make it white. But it is actually a light blue, mirroring the blue in the subject, the Earth.
Image is the Earth rising over the surface of the Moon as seen from Apollo 8 on December 24, 1968, and is in Public Domain courtesy of NASA.