If you are concerned about the output quality of your images in PowerPoint, then you may be interested to learn more about image resolution and the advanced options in powerpoint that let you handle this properly. In powerpoint, you can access advanced options page with a list of additional options that let you customize the way to use powerpoint. In File and then Options menu, you can open a screen like the image below.
Here you can change several options like editing options (what to do when selecint a text or an entire word), copy and paste options, or even display options.
But one of the most interesting options under this screen is the Image Size and Quality.
Here you can choose what to do with the images when discarding editing data is needed or do not compress image in file. There is also an option that let you set default target output and choose a list of PPI values for the image quality. Here you can change image resolution in powerpoint presentations.