When you crop an image, you remove data from or add data to the original image size to create a different image. Because you are removing or adding data relative to the original image, the concept of resampling loses much of its meaning. That's because the number of pixels per inch can vary based on the number of pixels in the crop selection area. When the number of pixels in the crop area allows, Photoshop tries to keep the same resolution of the original image. This method is considered cropping without resampling. However, when you are not exact about the number of pixels you select, the pixel dimensions and file size changes in the new image.