Cropping and resizing for printing- HELP!

Okay, so the image comes out of the camera. It is huge and needs to be resized for printing. There is extra stuff I don't want in the image so I first crop it out. Then, I use photoshop to resize it.

So, I want this image to print out as an 8 x 10. I try to choose 8 inches width and 10 inched height. But, it automatically keeps changing the width to 9.051 inches when the height is at 10. Is there any way I can over-ride this? And if not, what does this mean for when my image goes to printing?

Is it proper to crop out unwanted space before resizing? I would think if I resized to an 8 x 10 before cropping that cropping would again change the size?

Thanks for any help in advance.

Okay, so I answered one of my own questions with another minute of tinkering. There is a constrain proportions button I needed to uncheck. But, what does unchecking this box do? And what is the benefit of having it checked? Thanks again!

Best way to resize is using the crop tool. You'll see at the top image size and resolution boxes.

Open your original and then select the crop tool. Select the image size you want in px (pixels), cm (centimeters) or in (inches).

To print at native resolution leave the resolution box empty. Check the resolution by going to image>resize and you'll see the ppi value or you can interpolate and select the resolution you want (normally about 300ppi for a 10x8 image from an 8mp camera).

By unchecking "constrain proportions" you can then resize but you'll be stretching the image out of shape. Best not to do this.

When I select the crop tool, it does not give me an option to resize the image.

Also, if I do not select the constrain proportions, then it will not allow me to make it an
8 x 10, so how do I make it where it will be an 8 x 10 for printing?

look at the top of the screen after you select the crop tool.

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

I would like to know what version of PS you are using.. It could make a difference in the answer to your question.

The constrain selection means that you are not "deforming"your image, if you will. The constrain mean that it keeps the image the same dimensions albeit, smaller. If you do not constrain you will get a "squished" look to either the height or width of the image.

edit: By dimensions, I actually mean proportions.