How to change photo size to 300x300?

Your picture must be exactly 300x300 or 240x320 pixels. I have photoshop cs3. I would appreciate it if someone could send me a step by step instruction. I am new to photoshop and did try it but was not successful. by the way my current photo size is 640x480.How to change photo size to 300x300?
%26lt;Image

%26lt;Image Size...

A box should pop up

Input the pixel demension you desire

Make sure the bottom three boxes are checkmarked

(Scale Styles, Constrain Porportions, Resample Image)



Hit enter



Then

%26lt;File

%26lt;Save As...



Save it as a different file and keep the original higher resolution file in case you need to go back and do it over.



Edit:

One other thing, In this particular scenario, you desired image just happens to be the exactly half of what your current photo size is, so the proportions won't be out of whack... If you're ever in a situation where the Image needs a bit of cropping, For instance if your original was 640x500 and you needed 240x320, you should do the steps above except just change it to 320x250... that way it won't distort the photo, then after that click on

%26lt;Image

%26lt; Canvas Size

a Box should pop up, select the desired increment of measurement (Pixels) then change the image demensions to 320x240, It will tell you that it needs to crop, and it will ask you if you're sure that you want to do this, select yes, and you're good to go.