A Sprite Sheet is of course a Texture Atlas (see Wikipedia). Simple, right?
Oh you wanted to know details? Like, why you should use sprite sheets? What the benefits are? How sprite sheets save memory?
Then watch the vividly animated “Sprite Sheets – The Movie, Part 1” (aka Essential Facts Every Game Developer Should Know) courtesy of Andreas Löw:
You can find the transcript of the video on this page and the tool that can do all that (and more) is TexturePacker.
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