How to make two thumbnails for one job in a freelance portfolio?

Question

Freelance

It's easier to explain with an example.
Here is the account of one of the freelancers:
https://freelance.ru/piyavsa
We open the first job:
https://freelance.ru/piyavsa/2016-2655845.html
You can see the rest of the work there, you can clearly see that different pictures are used.
The previews of the work on the user's page and in the description are different, i.e. these are two different pictures
. If I insert a picture of the entire site into the preview, then on the main page it simply decreases in proportion and that's it, but here obviously people somehow set two different pictures.
How to do it? I don't understand.

Answer 1

very simple, after adding the work (it seems impossible to do this at the stage of adding), go to its editing, and there it will be possible to upload a preview