Php image crop and resized

PHP
1

I have to upload a image which is height=311 and width=238. Its not a proportional size. when i upload a image on that size, image will bad. If i got a php function which upload a image of that size which is height=311 and width=238 but original image is inner of that image and must be proportional.

The outer blank image must be of-white .

I am try to built but failed.

2

If using GD I would say you need to resize the image to the largest dimension then composite it onto a off-white image 311x238.

If using imagemagick resize the image to the largest dimension then use -extent to add the off-white background all in one go.