Hello,
Can I check how do I create a post that is shown in the demo: https://colorlib.com/activello/post-format-gallery/?
At the moment I am using a plug-in (Envira Gallery) to post the gallery photos but I like what was used in the demo better.
Looking forward to your reply
Thank you
Lynette
Hi there
Hope you are having a good day and thank you for your question 
just like in any wordpress theme it can be set as a gallery format from post format widget, check this link for more information:
regarding images they are default gallery images,
Envira has a different approach to the gallery, its very different from default gallery
Thanks!
Colorlib Support Team
Hi Noda
Got it! Thanks so much for the advice and help.
Best,
Lynette
Hello there,
I am glad the solution worked for you.
Please feel free to contact us again in the future regarding any other issues.
Best Regards,
Support