I checked and it appears that your site isn't allowing me to set custom image sizes.
Can you contact your host and ask them if the php-gd and php-gd2 modules are installed on your server as these will be needed to ensure that you can set the custom image sizes for cropping as well.
Unfortunately, because Web hosting is a shared platform, you cannot install modules per domain. You would have to look for an alternative, or look for a VPS.
As you can see through the link that my colleague Erik provided you, you can see that the 'GD' module is installed. As well as version 2 that your programming team is asking for. Please check the link my colleague Erik provided you again for this information. You can also check my screenshot to verify that the GD module is installed.
So, whatever your programming team needs to do should actually work. If what they want to do will still not work correctly, then you and your team must look into hosting your website on a self-managed VPS. You can view our VPS platform and available packages here: hidden link
As mentioned before, a VPS is completely self-managed. You can alter everything to your wishes, as well as installing modules in PHP that you need. However, this also comes with the fact that we cannot offer any assistance in managing the VPS. You will have to move the hosting of your website from your Webhosting package to a VPS and perform any necessary changes yourself. I hope for your understanding.
If you have any further questions, please don't hesitate to contact us again.