question about sprite sizes

I've been reading up a lot on sprites and how to optimize them. I read that it's best when using construct 2 to size the sprite to a power of 2 minus 2 pixels. But, I also read that you should always crop the transparent area off of the images before using them. So would it be better to have 20 to 30 126x126 sprites and keep the transparent areas or to crop them down and have 20 to 30 70x53 sprites, which would mean much less transparent pixels but not a power of 2 minus 2?

It is far better to crop them. A power of two minus two is not the optimal size - it's just the biggest size that fits neatly in to a power-of-two size sprite sheet (with 1px of transparent spacing). If you use a smaller size, you'll be able to pack more animation frames in to a single sprite sheet, which will save memory.

Thank you very much, that's exactly what I was hoping!