ckeditor upload images, to fix image size

we have been using ckeditor for some while, and now, wish to load a template (it has, say, 3 images) to ckeditor and let users to right click and change images

say, each of the 3 images have different width and height, for example

img1 : 200w x 300h

img2 : 350w x 250h

img3 : 400w x 350h

We wish, if user clicks img1, then resize user's image to max. 200w or 300h, if clicks img2, then resize user's image to max 350w or 250h, so that it won't expand the template

I wish it's a script resize but not HTML restrict

how can we use the uploader to resize different image blocks flexibly?