PowerPoint treats textures differently from pictures — both textures and pictures are bitmaps saved in pixel based formats like JPEG, GIF, BMP, PNG, TIFF, etc. The main difference between textures and pictures is that while textures are seamless, pictures are not necessarily seamless. Seamless means that if you tile up a texture, they will not show any edges while tiling thus provide an illusion of a seamless expanse. To learn more, explore the following links based on the version of PowerPoint you are using:
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