How To Offer Different Print Sizes

I have been thinking about this for some time and still haven't come up with a good solution hence the reason for asking what others do.

The way in which my Wordpress website works is that I have to create a price list and assign it a gallery.

The price list can almost be anything i choose for example;

10 x 10 = £w
11 x 14 = £x
10 x 8 = £Y
16 x 10 = £Z

Issue:
It's ok offering print sizes like above but what if the aspect ratio of the image does not fit into one of the above dimensions.
Say an image was taken on a 35mm camera with an aspect ratio of 3:2 which isn't really going to fit properly onto a 10x8.
And then there is the square format. I have had people in the past ordering a photograph which is in portrait format but they chose the 10x10 option.

How do you find the best way to overcome this issue when offering prints via your website.

Look at https://www.imagemagick.org/script/index.php

In my pages (made before I retired) I presented sizes as 'floating in [... whatever of the sizes you offer ...]'. So the actual image would fit on the paper. Disallow perfect fits because printing with nobleed does not really make most people happy. For perfect fits, simply add 1/4" border.

I think the funniest response I got was where a person asked how to handle a portrait image (say, 35mm aspect ratio) on 8x10. Uh, the software takes the longer side to fit the image, so the answer was "Just turn the paper upright."
.