Thumbnails to present your projects
Project presenting thumbnails have to be catchy, to attract a person to click on it and see a full project, if it's not visually attracting, there's a bigger chance that a person who might be your potential customer, just won't click it and will continue along online surfing journey to another website.
To make sure you raise the chance of person staying in your website, you need to make sure your project thumbnails are looking great, all shiny and beautiful, waiting for a visitor to click on it.
In this list of mockup resources websites, there will be free and premium(paid) ones, if you on a budget, you definitely can find great free ones, some of them are unrealistic, but if you keep on searching, there's a lot of good ones to choose from.
Websites links gathered from: Logodesignlove.com