Here's a PowerPoint utility I've been using recently that I thought would be useful to share. If you have two images on a slide and you're not interested in the backgrounds of the images, you may want to get rid of the image backgrounds. Why might you want to do this? For me, I wanted to overlap two images without having important content in one image blocked by unimportant content in the other. Take these two graphs showing how 11 brain regions interact with one another during a resting state scan in two different individuals (and check out this paper if you're interested in the connectivity method, the igraph package in R if you want to know how the graphs were drawn):
When side by side there's no issue. But I want to overlap them slightly. This is what happens why I try to do that:
Now the left-most node in the graph on the right is occluded by the background of the graph on the left. To avoid this, take the following steps: 1) select an image, 2) go to "Format Picture", 3) click "Remove Background". You should get something like this:
Now all you need to do is drag the inner most rectangle around so that it contains the content of the image that you want - like so (note that the selected content will get brighter as you select it):
Click on the "Remove Background" button when you've selected the content you want and BAM! The background is gone and your graphs can be overlaid without headache.
Thanks to Nilam Ram for this tip!