image help & adding a texture Options

[piggies]

im new.so bare with me,i know this is/maybe a dumb question.

how do i crop images to make it smaller.without it being pixely.like for blends.because when i go to paste the image into a new document on photoshop,its too big and when i try to crop it in paint,its all pixely.how would i crop images to make it smaller for photoshop?
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and how do i add a texture to images/blends...any easy way?

Thanks.