Why do vk use non-round values?

Question

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Hello! When working with the VKontakte API, I noticed that the contact stores images according to their specific sizes.
Their description is here: https://vk.com/dev/photo_sizes
And this is what interested me. Why are there sizes like:

• x is a proportional copy of the image with a maximum side of 604px;
  
• y is a proportional copy of the image with a maximum side of 807px;
  

Those. is there any really important reason to make the size not 600 or 800, namely 604 and 807. Maybe for the same reason it is worth storing images with such sizes in your projects?